Was he a traitor to his party? Or are his obvious breaches of his Jeffersonian and strict constitution ideals the result of the formation of parties and increased sectional differences? Was this compromise necessary?
I don't know if this can be answered from a strict historical point of view. You are asking very subjective moral questions about someone.
Remember that all humans (at least to some extent) have a "better nature" and a "meaner nature", are contradictory in their beliefs and actions, and engage in a certain amount of hypocrisy. Any exceptions to this generalization would be in figures held in high religious awe (Jesus, Mohammed, etc), which would be the exception that proves the rule.
Jefferson was aware of at least some of the contradictions he engaged in, and they made him uncomfortable. Whether you admire or despise the man is your own problem, and not really a part of "History".