18 U.S.C. § 593

Whoever, being an officer or member of the Armed Forces of the United States, prescribes or fixes or attempts to prescribe or fix, whether by proclamation, order or otherwise, the qualifications of voters at any election in any State; or Whoever, being such officer or member, prevents or attempts to prevent by force, threat, intimidation, advice or otherwise any qualified voter of any State from fully exercising the right of suffrage at any general or special election; or Whoever, being such officer or member, orders or compels or attempts to compel any election officer in any State to receive a vote from a person not legally qualified to vote; or Whoever, being such officer or member, imposes or attempts to impose any regulations for conducting any general or special election in a State, different from those prescribed by law; or Whoever, being such officer or member, interferes in any manner with an election officer’s discharge of his duties— Shall be fined under this title or imprisoned not more than five years, or both; and disqualified from holding any office of honor, profit or trust under the United States. This section shall not prevent any officer or member of the Armed Forces from exercising the right of suffrage in any district to which he may belong, if otherwise qualified according to the laws of the State of such district.