This case presents once again the troublesome problem of introducing evidence of a defendant's prior convictions to impeach his credibility, as authorized by 14 D.C.CODE § 305 (Supp. V 1966). Appellant asks that we reverse his conviction because the trial court's ruling on the admissibility of appellant's prior conviction was not in accord with our decision in Luck v. United States, 121 U.S.App.D.C. 151, 348 F.2d 763 (1965).

Appellant was convicted by a jury of assaulting a police officer with a dangerous weapon.1 The facts giving rise to the assault charge were not in dispute. On June 5, 1965, appellant was beaten severely by a group of boys, sustaining multiple fractures of his jaw. When two police officers arrived at appellant's home to render aid, appellant refused their assistance, went to a nearby carryout shop, and became involved in a fight with another youth. When the officers sought to intervene, appellant ran home, returned with a table knife, and refused to surrender the weapon despite warnings by the officers, both of whom confronted appellant with drawn guns. In spite of the drawn guns, appellant assaulted one of the officers with the table knife. Relying on testimony of the officers and two other witnesses describing his actions, appellant's defense was unconsciousness of his behavior at the time of the offense.

In support of the claim of unconsciousness trial counsel hoped to call appellant to the stand for his account of the events. Aware, however, that this could open the way for introduction in evidence of a prior conviction of assault with a dangerous weapon,2 counsel requested the court to rule the conviction inadmissible under the authority of Luck v. United States, supra.3 The request was denied4 and appellant decided not to take the stand.

In Luck we noted the problems involved in admitting prior convictions for impeachment purposes. 121 U.S.App. D.C. at 156-157, 348 F.2d at 768-769. Without doubt, reciting a defendant's prior criminal record to the jury can be highly prejudicial, especially where, as here, the prior offense is a crime similar to the one on trial. See Pinkney v. United States, 124 U.S.App.D.C. 209, 363 F.2d 696 (1966). Thus the impeachment rule confronts the defendant with a dilemma. Although his testimony may provide useful, even critical, information, he must weigh the prejudice that will attend exposure of his criminal record. Too often the defendant is kept from the stand or, having risked impeachment, is clearly prejudiced by admission of his prior record.5

It was with this experience in mind that we were led in Luck to hold that, while prior convictions might have some bearing on credibility, the trial court is not bound by 14 D.C.Code § 305 to permit impeachment in every case. Rather we called upon the trial court to exercise discretion, noting that "[t]here may well be cases where the trial judge might think that the cause of truth would be helped more by letting the jury hear the defendant's story than by the defendant's foregoing that opportunity because of the fear of prejudice founded upon a prior conviction. There may well be other cases where the trial judge believes the prejudicial effect of impeachment far outweighs the probative relevance of the prior conviction to the issue of credibility." 121 U.S.App.D.C. at 156, 348 F.2d at 768. (Footnote omitted.) We went on to mention some of the considerations that might be relevant in exercising that discretion, such as "the nature of the prior crimes, the length of the criminal record, the age and circumstances of the defendant, and, above all, the extent to which it is more important to the search for truth in a particular case for the jury to hear the defendant's story than to know of a prior conviction." 121 U.S. App.D.C. at 157, 348 F.2d at 769. (Footnote omitted.) Finally, we cited as "a highly desirable guide for the trial judge" Rule 303 of the American Law Institute's Model Code of Evidence (1942).6 121 U.S.App.D.C. at 156 n. 8, 348 F.2d at 768 n. 8.

In the case before us the trial judge unfortunately did not base his ruling on these individualized considerations. Instead he spoke of an "abstract" belief that those with prior convictions are likely to commit perjury because they fear the effect the prior conviction will have on their sentence should they be convicted again. As is obvious, should such an abstraction be permitted to prevail Luck would be rendered meaningless; if we accept the view that prior convictions provide such an impetus to commit perjury as to outweigh any prejudicial effect of impeachment, then we will have returned to the automatic impeachment rule Luck sought to change.

Moreover, the idea that a prior conviction provides a motive for perjury misconstrues the theory of impeachment. The reason for exposing the defendant's prior record is to attack his character, to call into question his reliability for truth-telling by showing his prior, relevant antisocial conduct. One need not look for prior convictions to find motivation to falsify, for certainly that motive inheres in any case, whether or not the defendant has a prior record. What greater incentive is there than the avoidance of conviction? We can expect jurors to be naturally wary of the defendant's testimony, even though they may be unaware of his past conduct.7 In fact, when the defendant does take the stand, the jury is charged to consider his interest in the outcome of the trial in assessing his credibility.

This is not to say that a prior conviction has no relevance to credibility. It is to say that the trial judge, in weighing the prejudice that might result from its admission against the interest in having the defendant testify, should focus on just how relevant to credibility a particular conviction may be.8 While one who has recently been convicted of perjury might well be suspected of lying again under oath, the fact that a defendant accused of assault has already been convicted of assault has no such bearing on credibility. Certainly the prior assault establishes a history of violent behavior, but proof of prior violent behavior is inadmissible to prove assault. See Michelson v. United States, 335 U.S. 469, 475-476, 69 S. Ct. 213, 93 L. Ed. 168 (1948).

Because the trial judge misconstrued his role under Luck, we cannot accept as a proper exercise of his discretion his ruling that appellant's prior conviction would be admissible. Indeed, when the facts established by the record are measured against the principles discussed here and in Luck, the ruling must be held erroneous. This is a classic illustration of a case in which "the prejudicial effect of impeachment far outweighs the probative relevance of the prior conviction to the issue of credibility." Luck v. United States, supra, 121 U.S.App.D.C. at 156, 348 F.2d at 768. Moreover, appellant's conduct at the time of the offense was critical to determining whether he was conscious of his behavior. To have his own account of his actions could well have aided the jury in resolving his claim of unconsciousness. To have foreclosed that account with the threat of impeachment did nothing to further the cause of truth.9 Thus whether viewed as a case where prejudice outweighs relevance to credibility or as one where it would be better to hear the defendant than not, the prior conviction should have been ruled inadmissible.10

Appellant also claims error with respect to certain comments made by the prosecutor during closing argument. This case involved the confrontation of a Negro youth and two police officers. Focusing on this, the prosecutor warned the jury that to acquit appellant would leave the police powerless to protect against such behavior short of resort to martial law.11

While such an argument is always to be condemned as "an appeal wholly irrelevant to any facts or issues in the case," Viereck v. United States, 318 U.S. 236, 247, 63 S. Ct. 561, 566, 87 L. Ed. 734 (1943), and as a dereliction of the prosecutor's high duty to prosecute fairly, see Berger v. United States, 295 U.S. 78, 88, 55 S. Ct. 629, 79 L. Ed. 1314 (1935), in the context of current events, raising the spectre of martial law was an especially flagrant and reprehensible appeal to passion and prejudice. Although the prosecutor "may strike hard blows, he is not at liberty to strike foul ones. It is as much his duty to refrain from improper methods calculated to produce a wrongful conviction as it is to use every legitimate means to bring about a just one." Berger v. United States, supra, 295 U.S. at 88, 55 S. Ct. at 633; Viereck v. United States, supra, 318 U.S. at 248, 63 S. Ct. at 567.

Reversed.