22 WATSON v. REPUBLICAN NATIONAL COMMITTEE Opinion of the Court on other grounds by Glasgow v. Moyer, 225 U. S. 420 (1912)); see Siebold, 100 U. S., at 392 (Congress’s power to regulate elections “supersede[s]” state law “so far as it is exercised, and no farther”). So even if plaintiffs are right about Mississippi law, they would still lose the challenge they have pressed in this litigation: that post-election-day ballot receipt is itself unlawful. * * * The Framers recognized the difficulty of crafting election laws “applicable to every probable change in the situation of the country.” The Federalist No. 59, at 362. So instead of constitutionalizing election law, they decided that “a discretionary power over elections” needed to be lodged “somewhere.” Ibid. Suffice it to say, that power was not lodged in this Court. The election-day statutes say nothing about ballot receipt, and we cannot add to the words Congress chose. The judgment of the Court of Appeals is reversed, and the case is remanded for further proceedings consistent with this opinion. It is so ordered.