"Treason against the United States, shall consist only in levying War against them, or in adhering to their Enemies, giving them Aid and Comfort."

and as an example of the nervousness, in Federalist No. 43 James Madison wrote:

"But as new-fangled and artificial treasons have been the great engines by which violent factions, the natural offspring of free government, have usually wreaked their alternate malignity on each other, the convention have, with great judgment, opposed a barrier to this peculiar danger, by inserting a constitutional definition of the crime, fixing the proof necessary for conviction of it, and restraining the Congress, even in punishing it, from extending the consequences of guilt beyond the person of its author."