In this appeal, George Collatos seeks review of his conviction of one count of perjury. He has raised three issues on appeal, none of which has sufficient merit to overturn his conviction. We, therefore, affirm.

In September of 1979, Collatos appeared as an immunized government witness at the extortion trial of Theodore Anzalone, an aide to former Mayor Kevin White of Boston. On cross-examination, Collatos suffered a severe "lapse of memory" with regard to a clandestine meeting clearly set up by Anzalone's counsel and which Collatos had attended with Anzalone at La Bella's coffee shop in Boston's North End.1 The content of that conversation formed the crux of Anzalone's defense. Collatos, the government's star witness, was thoroughly impeached by his "lack of recall" on cross-examination and Anzalone was subsequently acquitted.

Six months after Anzalone's acquittal, Collatos was indicted for perjury. The indictment charged that Collatos falsely testified that he did not remember his critical meeting with Anzalone at La Bella's. Collatos was subsequently convicted of the charge against him, but he contends that his trial was tainted by three errors of the District Court. He first argues that the Court erred in treating the materiality of his statements as a question of law rather than as one of fact for jury determination. Second, he contends that the closing argument of the government constituted improper comment upon his silence at trial. Finally, he takes issue with the Court's refusal to include certain of his requested interrogatories in its voir dire of the jury.

Collatos first asserts that the trial court erred in treating the issue of materiality as a question of law. Such an approach operates to deny him his right to a jury determination of all of the essential elements of the offense with which he was charged. Whatever the conceptual merit of this argument, it has long since been foreclosed by the opinion of the Supreme Court in Sinclair v. United States, 279 U.S. 263, 49 S. Ct. 268, 73 L. Ed. 692 (1929). In Sinclair, the Court stated that a question of materiality "is rightly decided by the Court as [a question] of law." Id. at 298, 49 S.Ct. at 273, 73 L. Ed. at 700. Every Circuit Court of Appeals,2 including the First Circuit,3 has followed the mandate of Sinclair and, in a perjury case, treated the issue of the materiality of a false statement as a question of law. In this case, we are compelled by our own precedent, and by Sinclair, to do likewise.

We recognize, as did the Fifth Circuit, that Sinclair represents an historical exception to the fundamental principle that "the judge must submit every essential element of the offense to the jury." United States v. Johnson, 718 F.2d 1317, 1323 (5th Cir.1983) (en banc). We are not free, however, to stray from the law as interpreted by the Supreme Court. Thus, although courts might be reluctant to "expand Sinclair's sweep at the expense of the accused's right to interpose the jury between himself and the judge," id. at 1324, in this case--which is squarely on point with Sinclair-- we apply its mandate and uphold the decision of the district judge.

It is hornbook law that a prosecutor, in closing argument, is at liberty to strike hard blows but not foul ones. Berger v. United States, 295 U.S. 78, 88, 55 S. Ct. 629, 633, 79 L. Ed. 1314, 1321 (1935). In this case, Collatos contends that the prosecutor hit below the belt when he stated in his closing argument "Now, I suppose it's a good defense, or at least it can be, to attack the government when you have no other defense." Without disclaiming that this was inaccurate or, indeed, that he had any particular defense,4 Collatos asserts that this argument was an improper comment upon his silence in violation of the rule in Griffin v. California, 380 U.S. 609, 85 S. Ct. 1229, 14 L. Ed. 2d 106 (1965). We disagree.

A claim of improper argument is evaluated under a "harmless error" standard. United States v. Hasting, 461 U.S. 499, 510-11, 103 S. Ct. 1974, 1981, 76 L. Ed. 2d 96, 107 (1983).5 This is so because there is no such thing as an error-free trial and, in the setting of a particular case, even some constitutional errors "are so unimportant and insignificant that they may, consistent with the Federal Constitution, be deemed harmless." Chapman v. California, 386 U.S. 18, 22, 87 S. Ct. 824, 827, 17 L. Ed. 2d 705, 709 (1967). In this case, we are convinced that if--and the if is a very big one--there was any Griffin error, it was harmless.

In Griffin, the Supreme Court held that the Fifth Amendment to the Constitution "forbids either comment by the prosecution on the accused's silence, or instructions by the Court that such silence is evidence of guilt." 380 U.S. at 615, 85 S.Ct. at 1233, 14 L. Ed. 2d at 110. The comment made by the prosecutor, however, was at worst an equivocal remark upon Collatos' lack of a defense,6 rather than even a whisper of an intimation regarding his failure to testify. It was uttered in response to a scathing defense attack upon the manner in which the government had conducted its investigation, and, in context, it appears that the government was merely attempting to buttress its contention that there was no reasonable doubt, indeed no doubt at all, regarding Collatos' guilt.

We have reviewed the whole record and are satisfied beyond a reasonable doubt that if--and the if is again a very big if--there was any error in the prosecutor's remarks, it was harmless.Invitation for Reversal

The final issue raised by Collatos concerns the voir dire of prospective jurors by the trial judge. Collatos had requested that the following two questions be directed to the venire members in order to probe their attitudes towards perjury:

(1) If the evidence in this case were that defendant had a prior conviction for perjury, would that affect your judgment in any way if no other credible evidence were produced by the government?

(2) if the evidence in this case were that defendant had been convicted of both perjury and extortion, would that affect your judgment in any way if no other credible evidence were produced by the government?

The District Court declined to ask the proposed questions. The judge reasoned that if there was truly no evidence of guilt other than Collatos' prior convictions, Collatos would be entitled to an acquittal as a matter of law on the grounds that his prior convictions constituted only impeachment evidence. Collatos contends, however, that the refusal to ask the proposed questions was an abuse of discretion. We disagree.

A defendant is not entitled to have specific questions directed to the jurors on voir dire. Ristaino v. Ross, 424 U.S. 589, 594-95, 96 S. Ct. 1017, 1020, 47 L. Ed. 2d 258, 263 (1976). Indeed, "the latitude and manner of voir dire examination is within the sound discretion of the district judge ... subject to the essential demands of fairness." United States v. Desmarais, 531 F.2d 632, 633 (1st Cir.1976) (quoting United States v. Gassaway, 456 F.2d 624, 626 (5th Cir.1972)). See also Parento v. Palumbo, 677 F.2d 3 (1st Cir.1982); Eastern Renovating Corp. v. Roman Catholic Bishop of Springfield, 554 F.2d 4 (1st Cir.1977). Collatos has failed to persuade us that the District Court's voir dire was insufficiently probing to satisfy the essential demands of fairness.

The questions proposed by Collatos would have placed the issue of his convictions before the jury prior to the time he testified at trial. Evidence of a prior conviction for perjury is generally admissible only to impeach the credibility of a witness who has already testified, Fed.R.Evid. 608, or under limited circumstances, as proof of other acts that are indicative of intent, motive, or identity. Fed.R.Evid. 609. Had the trial judge raised the issue of the prior convictions in the voir dire, before Collatos even took the witness stand, and worse, even before the trial began, he ran the risk of tainting the trial irreparably. We are hard pressed to discern how the District Court's decision to avoid that risk constituted an abuse of discretion.7 The Court below could properly exclude the requested questions from the voir dire.

The actions of the District Court were correct.

AFFIRMED.