Article III, Section 3 restricts treason to two acts: levying war against the United States or adhering to enemies by providing aid and comfort. The Framers defined treason in the Constitution to prevent Congress from expanding it to cover dissent or political opposition, as English law had done. The definition requires both elements: concrete action helping enemies and intent to betray the nation. The Supreme Court established that expressing traitorous thoughts alone cannot support conviction; the government must prove actual aid reached enemies. Levying war means assembling people to use force for treasonable goals, making all conspirators traitors whether present at the scene or not. Aid and comfort requires demonstrable assistance that strengthens enemies or weakens the United States. Courts interpret the definition narrowly, requiring prosecutors to prove each element beyond reasonable doubt. The constitutional definition prevents authorities from weaponizing treason charges against political opponents or protesters, distinguishing American law from authoritarian systems where treason encompasses criticism of leaders.