authority to protect its own legislative functions against corrupt efforts designed to impede legitimate fact-gathering and lawmaking efforts. See Watkins v. United States, 354 U.S. 178, 187, 206-207 (1957); Chapman v. United States, 5 App. D.C. 122, 130 (1895). Congress also has authority to establish a system of federal courts, which includes the power to protect the judiciary against obstructive acts. See U.S. CONST. ART. I, § 8, els. 9, 18 (“The Congress shall have Power . . . To constitute Tribunals inferior to the supreme Court” and “To make all Laws which shall be necessary and proper for carrying into Execution the foregoing powers”). The long lineage of the obstruction-of-justice statutes, which can be traced to at least 1831, attests to the necessity for that protection. See An Act Declaratory of the Law Concerning Contempts of Court, 4 Stat. 487- 488 § 2 (1831) (making it a crime if “any person or persons shall corruptly . . . endeavor to influence, intimidate, or impede any juror, witness, or officer, in any court of the United States, in the discharge of his duty, or shall, corruptly . . . obstruct, or impede, or endeavor to obstruct or impede, the due administration of justice therein”). ii. The Article III courts have an equally strong interest in being protected against obstructive acts, whatever their source. As the Supreme Court explained in United States v. Nixon, a “primary constitutional duty of the Judicial Branch” is “to do justice in criminal prosecutions.” 418 U.S. at 707; accord Cheney v. United States District Court for the District of Columbia, 542 U.S. 367, 384 (2004). In Nixon, the Court rejected the President’s claim of absolute executive privilege because “the allowance of the privilege to withhold evidence that is demonstrably relevant in a criminal trial would cut deeply into the guarantee of due process of law and gravely impair the basic function of the courts.” 407 U.S. at 712. As Nixon illustrates, the need to safeguard judicial integrity is a compelling constitutional interest. See id. at 709 (noting that the denial of full disclosure of the facts surrounding relevant presidential communications threatens “[t]he very integrity of the judicial system and public confidence in the system”). iii. Finally, the grand jury cannot achieve its constitutional purpose absent protection from corrupt acts. Serious federal criminal charges generally reach the Article III courts based on an indictment issued by a grand jury. Cobbledick v. United States, 309 U.S. 323, 327 (1940) (“The Constitution itself makes the grand jury a part of the judicial process.”). And the grand jury’s function is enshrined in the Fifth Amendment. U.S. CONST. AMEND. V. (“[n]o person