Jefferson believed that the legislative authority had the sole responsibility of judging matters of impeachment.
High crimes and misdemeanors were subjective terms not necessarily synonymous with actual crimes.
“There is another opinion entertained by some men of such judgment and information as to lessen my confidence in my own. That is, that the Legislature alone is the exclusive expounder of the sense of the Constitution in every part of it whatever. And they allege in its support that this branch has authority to impeach and punish a member of either of the others acting contrary to its declaration of the sense of the Constitution.” –Thomas Jefferson to W. H. Torrance, 1815