Under section 1512(d): "it is an affirmative defense, as to which the defendant has the burden of proof by a preponderance of the evidence, that the conduct consisted solely of lawful conduct and that the defendant's sole intention was to encourage, induce, or cause the other person to testify truthfully." 18 U.S.C. § 1512(d). This allocation of the burden of proof to the defendant has led some to question the constitutionality of this section.
Affirmative defenses, such as the one created by 18 U.S.C. § 1512(d), expose a tension between two principles of constitutional law. Historically, the Supreme Court has held that it is constitutionally permissible for legislatures to establish affirmative defenses to criminal charges and place the burden of proof with respect to these defenses on the defendant. See Leland v. Oregon, 343 U.S. 790 (1952) (insanity defense). Yet the Court has also clearly held that the Constitution requires that the government prove all elements of a criminal offense beyond a reasonable doubt. In re Winship, 397 U.S. 358 (1970).
Due process is satisfied when the government is required to prove all of the elements of the offense, as defined by the legislature. Due process does not require that the government accept the additional burden of disproving every fact constituting an affirmative defense to the charge.
The affirmative defense established by 18 U.S.C. § 1512(d) provides an excellent example of this principle. Section 1512 generally proscribes someone from knowingly intimidating another person with the intent to influence, delay or prevent that person's testimony. Therefore, a prosecution under 18 U.S.C. § 1512 would require the government to prove beyond a reasonable doubt: (1) an effort to threaten, force or intimidate another person; and (2) an intent to influence that person's testimony. Once the government had proven both an act of intimidation and an intent to influence the testimony of another, it would be entitled to a conviction unless the defendant could take advantage of the limited affirmative defense provided by 18 U.S.C. § 1512(d). This defense would only become an issue, however, after the government had carried its initial burden of proof on all of the elements of the offense. Courts considering this issue have held that the provision does not unconstitutionally shift the burden of proof. See United States v. Kalevas, 622 F. Supp. 1523 (S.D.N.Y. 1985). See also United States v. Thompson, 76 F.3d 442 (2nd Cir. 1996); United States v. Johnson, 968 F.2d 208 (2nd Cir.), cert denied, 506 U.S. 964 (1992); United States v. Clemons, 658 F. Supp 1116, affirmed, 843 F.2d 741, (3d Cir.), cert denied, 488 U.S. 835 (1988).
[cited in USAM 9-69.100]