Each of the appellants was convicted at a separate non-jury trial held in the District Court for the District of Puerto Rico of entering upon a United States naval reservation in violation of 18 U.S.C. § 1382.1 Of their numerous challenges to the convictions and ensuing sentences, the most substantial is their contention that in each case the government failed to prove all elements of the offense charged. We agree, and on this basis are constrained to reverse the convictions.

Appellants were among 21 persons arrested on May 19, 1979 at Bahia de la Chiva, also known as Blue Beach, located on the southeastern coast of the island of Vieques. The United States Navy owns approximately 76 percent of Vieques, a municipality of the Commonwealth of Puerto Rico, and periodically conducts military operations there, including exercises in weapons fire and amphibious landings. See Romero Barcelo v. Brown, 643 F.2d 835, 838-840 (1st Cir. 1981). On May 19, 1979, the Navy planned to use Bahia de la Chiva as part of an amphibious maneuvers exercise.

The district court took "judicial notice" that for over a year preceding appellants' arrests there had been widely publicized controversy regarding the Navy's presence on Vieques. At the trials of Tio and Trevathan, evidence was introduced indicating that demonstrations against the Navy had been conducted on Vieques, and on Bahia de la Chiva in particular, during the week prior to May 19, 1979.2 One such incident occurred on May 16, 1979, when a group of fishermen attempted to disrupt an amphibious landing on Bahia de la Chiva.3

Nineteen of the 21 persons arrested on May 19, 19794 (including appellants) were charged in separate informations with violating section 1382 by "(going) upon Bahia de la Chiva Beach, also known as Blue Beach, Camp Garcia Annex, U.S. Naval Station, Roosevelt Roads, for a purpose prohibited by lawful regulation, in that (they) did enter without proper authorization from the Commanding Officer as required by Title 32, Code of Federal Regulations, Section 765.4 and NAVSTAINST 5510.9H of November 9, 1978." Although appellants stood trial separately, both the evidence presented against them and the district court's findings were largely the same, as follows.

Lieutenant Commander Samuel Meiss, attached to the Special Warfare Group at Roosevelt Roads Naval Station, Puerto Rico,5 testified that about 7:00 a. m. on May 19, 1979 he received orders to deploy security forces to Camp Garcia, following reports that a number of privately owned ships had been sighted in the vicinity of Blue Beach. His forces, 30 uniformed Navy security personnel, were transported from Roosevelt Roads to Vieques by helicopter. Once there, they approached Blue Beach by land, in two separate groups. When Meiss first arrived at Blue Beach, between 10:00 a. m. and 12:00 noon,6 he stationed himself and his men behind a line of trees. He observed about 200 people "milling about" on the beach and noticed that some tents had been pitched there. A large number of craft were drawn up on the beach. During the time he was present, Meiss saw at least three of the appellants at a point above the "brim line" or "high water mark" on the beach.7 Soon after his arrival, the two groups of security personnel consolidated and moved out in plain view of the civilians; shortly after that, Admiral Knoizen, Commander of Naval Forces, Caribbean, ordered Meiss to detain the civilians. The detention process, which was marked by minor altercations, lasted about an hour, during which time many of the 200 persons retreated to boats and left the area.8 Nineteen persons were forceably detained and taken aboard a Navy landing craft; appellants Parrilla and Trevathan walked aboard the landing craft voluntarily and were arrested along with the other detainees.

Alexander de la Zerda, a naval liaison officer on Vieques, testified that the usual procedure for entering Camp Garcia, to which Blue Beach is appended, is to proceed through a main gate, located about four miles from Blue Beach, and obtain a visitor's pass. He testified further that two "roving patrols" traverse Camp Garcia and the adjacent Navy lands on a regular basis, searching for unauthorized personnel. During the first week in May 1979, de la Zerda participated in the distribution of a document warning "fishermen and other interested persons" not to use certain of the waters surrounding Vieques during the week of May 14-20, 1979, because of potentially dangerous Navy activities. Copies of the notice were given to the Fishermen's Association on Vieques and were posted at the Vieques police station, post office, and at the front gate of Camp Garcia.

Tommy Thompson, security officer at the Roosevelt Roads Naval Station, testified concerning the procedure governing entrance to the naval reservation on Vieques, a procedure embodied in Naval Instruction 5510.9H, which was introduced into evidence. In brief, non-military personnel must obtain a pass to enter the naval base. Based on his search of the relevant records, Thompson testified that no passes were issued to appellants on May 19, 1979. According to Thompson, apprehended trespassers are usually brought to the security office and given a letter barring reentry on the naval facility; Thompson admitted that this procedure, and other of the "normal procedures" for dealing with apprehended trespassers, were not followed in these cases.9

Joseph Loyacano, a member of the Navy's Civil Engineer Corps, testified primarily concerning a map and written description of Navy property on Vieques taken from court records of the 1942 condemnation proceedings pursuant to which the United States acquired private lands on Vieques for the establishment of fleet operating facilities.10 With reference to these documents, Loyacano testified that Bahia de la Chiva was included within the Navy's property, and that the southern border of the Navy's land at this point was the "ordinary high tide line." In addition, the government introduced a certification from the Registry of Property, Humacao Section, Puerto Rico, showing that title to the parcel to which Loyacano referred is registered in the name of the United States.11

18 U.S.C. § 1382 provides, in relevant part:

"Whoever, within the jurisdiction of the United States, goes upon any military, naval, or Coast Guard reservation, post, fort, arsenal, yard, station, or installation, for any purpose prohibited by law or lawful regulationShall be fined not more than $500 or imprisoned not more than six months, or both."12

The informations charge appellants with entering Camp Garcia Annex for the purpose of violating 32 C.F.R. § 765.4 and Naval Instruction 5510.9H, both "lawful regulations." See part I, supra. 32 C.F.R. § 765.4 provides that "access to any naval activity" is subject to the authorization and control of the officer in command and to "restrictions prescribed by law or cognizant authority." Naval Instruction 5510.9H, an internal, unpublished Navy document, requires, inter alia, that persons entering Camp Garcia obtain authorization and receive a pass. In essence, then, appellants are charged with entering a restricted naval reservation "for the purpose" of entering without authorization.

There is a threshold question whether these informations are sufficient to allege the elements of a section 1382 violation. Appellants and the government agree that one element of the offense is unauthorized entry on a restricted United States military reservation. Appellants contend, however, that the government must allege and in addition that the trespasser intended to commit a crime other than the entry itself, such as arson, larceny, or espionage. Alternatively, appellants argue that the government must allege and demonstrate the defendant's "specific intent" to violate the precise regulation restricting access to the military facility.

We conclude, in essential agreement with virtually every other court that has considered the issue, that the requisite prohibited "purpose" under section 1382 can consist of unauthorized entry itself, and that no "specific intent," in the strict sense, to violate the law or regulation prohibiting such entry need be shown. United States v. Mowat, 582 F.2d 1194 (9th Cir.), cert. denied, 439 U.S. 967, 99 S. Ct. 458, 58 L. Ed. 2d 426 (1978); United States v. Floyd, 477 F.2d 217 (10th Cir.), cert. denied, 414 U.S. 1044, 94 S. Ct. 550, 38 L. Ed. 2d 336 (1973); see also United States v. Holmes, 414 F. Supp. 831 (D.Md.1976); United States v. Bishop, 261 F. Supp. 969 (N.D.Cal.1966); cf. United States v. Patz, 584 F.2d 927, 929 (9th Cir. 1978). Such an interpretation is suggested by the words of the statute, which prohibit entry for any purpose prohibited by a lawful regulation. This language does not indicate a requirement that the defendant harbor a "specific intent" to violate a particular regulation, only that he act with a "purpose" that is in contravention of the regulation's terms. Nor does the statute attempt to limit the class of regulations violation of which will serve as an element of the offense. Furthermore, as suggested in United States v. Mowat, supra, 582 F.2d at 1204, it is highly unlikely that Congress intended section 1382, a "petty offense" carrying relatively light maximum penalties, to apply only in cases where the government can show beyond a reasonable doubt that a defendant intended to commit a serious crime such as espionage or destruction of property when he entered the military reservation.

On the other hand, when a section 1382 prosecution proceeds on the basis that the defendant has entered a restricted military reservation "for the purpose of" unauthorized entry, we think it must be shown that the defendant had knowledge or notice that such entry was, in fact, prohibited.13 See United States v. Floyd, supra, 477 F.2d at 225. Cf. United States v. Patz, supra, 584 F.2d at 929 ("The usual situation in which 18 U.S.C. § 1382 is applicable is that in which the entry is with knowledge that the facility has been closed to the public by properly promulgated regulations of the military commander."). Section 1382 is not a "general trespass statute," id., and was not intended to impose criminal liability on "innocent trespassers." Holdridge v. United States, 282 F.2d 302, 309 (8th Cir. 1960). Congress might have made criminal any entry without permission upon a military base; this it did not do. Instead, it established as requisite to the criminality of initial trespasses that entry be made for a purpose prohibited by law or regulation. The word "purpose" imports at least some sort of culpable design or mental state. See Holdridge, supra, 282 F.2d at 309. When the proscribed "purpose" consists of no more than the entry itself, we think the clear implication is that, at a minimum, the defendant had notice of the prohibition of entry upon the military reservation, yet entered anyway.

Were we to hold otherwise, we would render the second paragraph of section 1382 largely surplusage. That paragraph prohibits reentry onto military property, regardless of "purpose," after the trespasser has been "removed therefrom or ordered not to reenter by any officer or person in command or charge thereof." See note 12, supra. As noted in Holdridge, supra, 282 F.2d at 308-09, "(t)his paragraph thus involves a second invasion of the premises and one where the accused, because of his prior physical removal or the formal order, is definitely aware that re-entry is prohibited." There would have been little reason, however, for Congress to include this paragraph directed at "second invasions" were trespassers rendered liable under the first paragraph of section 1382 for any unauthorized entry onto a restricted military base, without regard to their "awareness" that the entry was unlawful. Indeed, the interpretation we adopt here simply harmonizes the two paragraphs of section 1382. Thus, persons may not enter military reservations that are closed to them, provided they have notice or knowledge that their entry is prohibited. When such advance notice or knowledge is demonstrated, persons may be criminally prosecuted under section 1382 for an initial trespass. When such notice or knowledge is not shown as regards the initial entry, removal or an order not to reenter establishes the requisite knowledge for purposes of subsequent entries.

We now turn to appellants' contention that the government's evidence was insufficient to prove that they entered Blue Beach with knowledge or notice that their entry was unlawful. The evidence in the individual trial records before us is indeed scant on this score. There was no evidence appellants had ever seen, or even knew of the existence of, Naval Instruction 5510.9H. This, by itself, was by no means fatal. It would have been enough to have shown that appellants reasonably understood that naval authorities had declared the base closed to all persons who lacked passes or other authorization. As we have pointed out, however, a trespasser on a military reservation who is without notice or knowledge that the reservation has been closed to the public, violates section 1382 only if he reenters after first being warned off. It follows that knowledge cannot be inferred from the mere fact that it was a military installation upon which entry was made. Something more must be shown. When appellants came on Blue Beach on May 19, 1979, they were not confronted by a fence or other visible boundary marking from which to infer the Navy's closing of the installation to outsiders.14 Although uniformed Navy security personnel later appeared on the scene,15 they began making arrests within a few minutes thereafter,16 and there was no evidence that they warned appellants to leave the beach prior to making the arrests.17 Nor were there any signs posted to warn appellants that entry onto the beach was prohibited.18 Indeed, the only sign on the beach read as follows:

YOU ARE NOW A GUEST ON THIS U.S. MILITARY RESERVATION. ENJOY

YOURSELF AND CLEAN UP AFTER YOURSELVES.

The district court did point to several factors aside from the happenings on the beach as being "circumstantial evidence" that appellants knew their entry onto Blue Beach was unlawful. First, the court found that notices warning of the Navy's amphibious maneuvers on May 19, 1979 had been posted and distributed on Vieques. This notice, however, simply "informs" fishermen of the Navy's activities, and warns that the activities "can be dangerous to personnel and fishing equipment."20 Leaving aside the fact that the notice does not indicate that entry into the danger zones is unlawful, the notice is directed only toward entry into the waters off Vieques; it would not directly inform potential trespassers that entry upon the lands encompassed by Camp Garcia has been forbidden by law or regulation.21

In Berkan's case, the district court cited, as evidence of notice, the fact that Berkan had represented the Vieques Fishermen's Association in a civil action, United States v. Zenon, wherein the court had enjoined not only the Association but also its "officers, agents, servants, employees, attorneys, members, aiders, abettors, sympathizers, and any and all persons in active concert or participation with them" (emphasis added) from:

"(1) unlawfully entering, or remaining therein, the navigable waters of the restricted area established and published in 33 Code of Federal Regulations 207.815(a)(3), specifically being a strip 1,500 yards wide on the South coast of the Island of Vieques, Puerto Rico, extending from the entrance to Port Mosquito east to Conejo Point,

(2) unlawfully entering, or remaining therein, the navigable waters of the danger zone established and published in 33 Code of Federal Regulations 204.234, specifically being in the waters of the Caribbean Sea and Vieques Sound in the vicinity of the Eastern Vieques bombing and gunnery target area,

(3) unlawfully entering all federal lands located in the Island of Vieques, Puerto Rico."

Were Berkan charged with violating 33 C.F.R. §§ 207.815 or 204.234, or in any other manner with unlawful conduct on the waters off Vieques, the first two prongs of this injunction would be relevant; we have already noted, however, that this was not the case. As for the last prong of the injunction, its relevance is also severely limited in this context. This was not a criminal contempt prosecution, nor does the government contend that, in the absence of a law or regulation prohibiting entry generally, going upon a military reservation in contravention of a court order directed to a restricted group of people is the same as going upon such a reservation for a "purpose prohibited by law or lawful regulation," in violation of section 1382.22 Nor does Berkan's constructive notice of the injunction suffice to show her knowledge of the contents of Naval Instruction 5510.9H, which she was charged with violating.

The district court also viewed the fact that Parrilla and Trevathan "voluntarily walk(ed) upon the landing barge without any interference from security personnel" as "establish(ing)" their "full knowledge" that they were present at Blue Beach illegally. This inference was, in our view, unwarranted. Such action could just as likely have been a gesture of solidarity with those who were arrested, or an attempt to avoid violence, as anything else. Indeed, it would be somewhat far-fetched to construe the voluntary boarding of the landing craft as an "admission of guilt."

Finally, the district court stressed that "widespread media coverage" had "focused the public's attention" on the Navy's "military installations" on Vieques and on prior disruptions of amphibious exercises. The court found it "noteworthy" that appellants' presence on Blue Beach coincided with the Navy's conducting of amphibious operations. If the record had in fact established appellants' knowledge that amphibious landings were to take place on Blue Beach on May 19, 1979, we might well agree that this demonstrated notice that the area was closed to the public on that day. The scheduled occurrence of dangerous military operations would suggest to most people that those in charge had closed off the area. There is little in the records of these cases, however, to show that appellants had foreknowledge of the impending military activities. While scattered bits of testimony in the records of some of the trials indicate that the navy did, in fact, conduct operations on Blue Beach on May 19, 1979, the records also suggest that such activities were not taking place on the beach, or in the nearby vicinity, during the period of appellants' presence there.23 Lieutenant Meiss's description of the arrests indicates at least that there were no Navy craft attempting to land on the beach and unload personnel and equipment during the hour that the detentions took place. The notice to fishermen, discussed supra, did label one of the "danger zones" in the ocean off the south coast of Vieques as "Amphibious Op Area South."24 There is nothing in the notice, however, elaborating on this designation, explaining what kinds of activities take place in the "Amphibious Op Area," or notifying exactly where on what appears to be a several mile stretch of beach this activity would proceed. Equally troublesome, there is nothing except the fact that this notice was distributed to several locations on Vieques to show that appellants actually saw the notice or were likely to have done so.

We are nevertheless left with the fact that appellants were part of a large group of people who managed to show up at Blue Beach on a date when amphibious maneuvers were scheduled to take place there. The district court, apparently evaluating this fact in light of its independent knowledge that the "media" had "frequently addressed" the subject of amphibious landings on Vieques (and perhaps its own familiarity with appellants' purposes and mode of operation), concluded that "common sense and experience tells this Court that (appellants) must have known and been aware that Blue Beach was situated within this Naval installation."25 While this conclusion may well be correct, there are obvious limits to the extent which "common sense and experience" insofar as this consists of knowledge beyond the scope of the record in a particular case can substitute for proof at a criminal trial. Indeed, whatever the propriety of taking judicial notice of newspaper articles and the like for purposes of demonstrating a critical element of the government's case, this was not actually attempted here. The parties never moved that the court notice particular newspaper articles, nor did the court inform the parties that it intended to take such notice on its own motion. Cf. Fed.R.Evid. 201(e). Furthermore, the district court's findings refer to nothing more specific than "widespread media coverage" of the Navy's previous operations on Vieques; we are hard pressed to see how this can serve to establish these particular defendants' knowledge and notice of Navy restrictions on the use of Blue Beach.26

Thus even giving the government the benefit of every possible inference, it is doubtful whether the record supports a finding that appellants reasonably knew that their presence was forbidden whether on the theory that they knew that dangerous exercises were imminent, or on some other theory.

Still, if the issue of notice or knowledge were the sole weak spot in the government's proof, a reviewing court might be sorely tempted to stretch a point, and deferring to the trial court's first-hand familiarity presume a "common sense" basis for finding that appellants had meant their entry to coincide with military exercises, and thus occur when reasonable people would know the reservation was closed. As we discuss in the next section, however, an even more serious deficiency exists, requiring us to reverse the convictions regardless of whether we were to adopt such a relaxed approach to the issue of notice or knowledge.

Perhaps the most obvious and basic element of a section 1382 prosecution is a demonstration that the defendant entered a "military reservation," "within the jurisdiction of the United States." Appellants contend that the government failed to make such a demonstration here, and surprising as it may appear, they seem to be right.

The evidence and testimony put forth by the government in the various cases proceeded on the theory that the southern border of Camp Garcia runs along the "ordinary high tide line" of the Caribbean Sea. The government's presentation indicated acceptance of the proposition that appellants' penetration of the "ordinary high tide line" was something the prosecution had to prove, and would prove, as a necessary element of its case. The government attempted to demonstrate that appellants had crossed this line through evidence placing appellants, at some point prior to their arrests, either "on dry sand" or landward of the "brim line" or "brim crest."27 In spite of appellants' contention that neither the berm line nor any other visible line of erosion is equivalent to the "ordinary high tide line" (said to be substantially inland of the visible markings),28 the district court ruled that Camp Garcia's southern border "extends to the ordinary high tide line or brim line of the Caribbean Sea," (emphasis added) and found that appellants had all been present on Blue Beach above the "brim line."

On appeal, appellants renew their contention that the berm line is insufficient as a representation of Camp Garcia's southern border. In response, the government has substantially changed its tack. In oral argument before this court, counsel for the government conceded that "if, in fact, the ordinary high tide line is the boundary of the base, then the government failed to prove (appellants) crossed it." Nor does the government now argue that the berm line is the correct border, and that the appellants were shown to have passed this line. Instead, the government now maintains that Camp Garcia encompasses Blue Beach in its entirety, so that it is immaterial where on the beach appellants were shown to have been located. The government argues that the United States acquired title to the Vieques shores and surrounding waters from the Spanish Monarchy in 1899; contends that while Congress has placed the "harbor areas and navigable streams and bodies of water and submerged lands underlying the same in and around the island of Puerto Rico" under "the control" of the Commonwealth, 48 U.S.C. § 749, the United States retains "actual ownership" of the submerged land; and concludes that it would be "absurd" to maintain that the boundaries of a naval base do not extend to the water, particularly when the United States condemned the adjacent land expressly to establish "fleet operating facilities."

The government's recent position may well, for all we know, be correct. The difficulty is, it was never presented in or to the district court, and therefore comes to this appellate tribunal without benefit of findings or rulings below, and without defendants' having had the chance to confront it at trial. Moreover, the validity of the government's present theory is not self-evident. Had the government unveiled it at trial, appellants would have had respectable grounds to try to contest it. Appellants say they would have maintained that the surface of the beach below the high tide mark is, in fact, "owned" by the Commonwealth of Puerto Rico, and thus cannot be implied to have become part of the naval reservation.29 Arguably, the United States "ceded" to the Commonwealth, in 1917, whatever interests in such land it acquired from the Spanish Crown. See 48 U.S.C. §§ 746, 747 & 749; Commonwealth of Puerto Rico v. SS Zoe Colocotroni, 456 F. Supp. 1327, 1336 (D.P.R.1978) ("The United States has transferred to the Commonwealth all interest it had in the navigable waters of Puerto Rico and their resources, and in the submerged lands and their resources The Commonwealth has title to all beaches and to the maritime terrestrial zone abutting the navigable waters "), aff'd in relevant part, 628 F.2d 652, 670 (1st Cir. 1980). See also Rubert Armstrong v. Commonwealth, 97 P.R.R. 573, 596-616 (1969).

The government does not seem to deny that in 1917 the United States may have transferred away at least some of its rights in the Vieques beaches. It argues instead that the 1942 condemnation of private property to establish fleet operating facilities, and the statutes authorizing and appropriating money to carry out this condemnation, were "intended to destroy whatever rights previously belonged to the people of Puerto Rico with regard to the shoreland surrounding the property taken from the Eastern Sugar Associates."30 But cf. 48 U.S.C. § 748 ("President may from time to time accept by legislative grant from Puerto Rico any lands, buildings, or other interests or property which may be received for public purposes by the United States") (emphasis added). Alternatively, the government asks us to find that the United States has acquired ownership of Blue Beach through "adverse possession," a finding it must surely realize would require a factual predicate not to be found in the records before us.31

We hold that, regardless of Camp Garcia's "true" border, the government is bound for purposes of these prosecutions by the border line it established at trial a line it now concedes appellants were not shown to have passed. We reach this conclusion for two reasons. First, to uphold appellants' convictions upon a theory never presented to the district court would raise serious questions of due process. Dunn v. United States, 442 U.S. 100, 106-07, 99 S. Ct. 2190, 2194, 60 L. Ed. 2d 743 (1979) ("To uphold a conviction on a charge that was neither alleged in an indictment nor presented to a jury at trial offends the most basic notions of due process (A)ppellate courts are not free to revise the basis on which a defendant is convicted simply because the same result would likely obtain on retrial."); Cole v. Arkansas, 333 U.S. 196, 201, 68 S. Ct. 514, 517, 92 L. Ed. 644 (1948) ("No principle is more clearly established than that notice of the specific charge, and a chance to be heard in a trial of the issues raised by that charge, if desired, are among the constitutional rights of every accused in all courts "); id., at 202, 68 S.Ct. at 517 ("To conform to due process of law, petitioners were entitled to have the validity of their convictions appraised on consideration of the case as it was tried and as the issues were determined in the trial court."). See also Presnell v. Georgia, 439 U.S. 14, 99 S. Ct. 235, 58 L. Ed. 2d 207 (1978); Gregory v. Chicago, 394 U.S. 111, 122-24, 89 S. Ct. 946, 952-53, 22 L. Ed. 2d 134 (1969) (Black, J., concurring); Spevack v. Klein, 385 U.S. 511, 518, 87 S. Ct. 625, 629, 17 L. Ed. 2d 574 (1967). Cf. Goodloe v. Parratt, 605 F.2d 1041 (8th Cir. 1979) (prosecution's change of theory during trial violated defendant's due process rights, by creating variance between the information and the theory on which case was tried).

Furthermore, appellate courts will not ordinarily consider theories presented for the first time on appeal. Johnston v. Holiday Inns, Inc., 595 F.2d 890, 894 (1st Cir. 1979); Martinez Moll v. Levitt & Sons of Puerto Rico, Inc., 583 F.2d 565, 571 (1st Cir. 1978); Dobb v. Baker, 505 F.2d 1041, 1044 (1st Cir. 1974); Roto-Lith, Ltd. v. F. P. Bartlett & Co., 297 F.2d 497, 500 (1st Cir. 1962); Bird v. United States, 241 F.2d 516, 520-21 (1st Cir. 1957). While this principle has most often been applied in civil cases, it has also been invoked in criminal cases to bar the government from seeking to uphold a conviction on a newly presented ground. United States v. Patrin, 575 F.2d 708, 712-13 (9th Cir. 1978); Sizemore v. United States, 393 F.2d 656 (8th Cir. 1968). We think "the fundamental precept that issues on appeal are to be confined to those duly presented to the trial court," Jordan v. United States Department of Justice, 591 F.2d 753, 779 & n.14 (D.C.Cir.1978), has force in a criminal proceeding such as this where the evidence is concededly insufficient to support the convictions below on the theory on which they were obtained.32

The government contends that "(t)he boundary of the Naval Station is a legal question that this Court may properly determine for itself, on the basis of the Treaty of Paris, the statutes cited in our brief , and the historical facts established in the Barcelo v. Brown opinion," see note 31, supra. Plainly, however, the resolution of this "legal question" is not "obvious," cf. Martinez Moll, supra, 583 F.2d at 571. While the government's new contentions are far from "frivolous," "neither (are they) self-evident." Dobb v. Baker, supra, 505 F.2d at 1044. Especially considering the potential importance that resolution of these issues may have for the Commonwealth, we are disinclined to embrace the government's eleventh hour position on the basis of the undeveloped records here.

We, of course, express no opinion on the boundaries of the naval reservation on Vieques or, in general, on the question of the "ownership" of Puerto Rico's shorelands. We hold only that the government failed to prove its case on the theories it advanced before the district court, and that it is now too late to save these prosecutions through advancement of a different "theory of the case."33

As the convictions must be reversed for the reasons described, it is not necessary to address the other issues raised by appellants and amici curiae.

The convictions are hereby reversed.