Former Democrat Hawaii Rep. Tulsi Gabbard is taking legal action against Republican Utah Sen. Mitt Romney after he accused her of being a traitor.

“Tulsi Gabbard is parroting false Russian propaganda. Her treasonous lies may well cost lives,” Romney tweeted on March 13.

Treason is a heavy accusation defined as something that “shall consist only in levying War against them, or in adhering to their Enemies, giving them Aid and Comfort. No Person shall be convicted of Treason unless on the testimony of two Witnesses to the same overt Act, or on Confession in open Court.”