You can judge your leaders by whether they agree with you or not. But if they don't produce consequences that are good for the long-term best interests of the society - which is to say all of us - then they may simply be toxic (to use a popular term in its popular use).
Look first to determine how superbly they performed their leadership role in all of its aspects. For example, CEOs have a moral obligation to make the larger economy better than it was when they stepped into that role. Their role says they are to serve the best self-interests of all of their stakeholders, not just those who track only the numbers.
Then measure the consequences some 20 or 30 years after they have left office. What President has not promised to make a better world for all of us? If you bought into that, how's that working for you?
Recently the Harvard Business Review (blogwise) offered an open forum on the question: "Should leaders be 'frank' or 'deceptive'?" That a really weird question. Are we to imagine Hamlet asking, "To be or not to be 'frank'? - that is the question." Or "To be or not to be 'deceptive'? - that is the question." And since when is candor or deception - like "love" - not in the eye of the beholder?
The question is surely not "frank" - since the asker does not reveal what's in it for him. And if the "leader" is not "frank," does that mean necessarily that she is being "deceptive?"
But that's what definitions can do for you. They can lead you down dead-end streets. If a "leader" is just a bag of tricks, why would we need a new term for that? We've had those people and many names for them since the beginning of time. Or did human history begin in 1980?