C minus 25 - the leadership conundrum

It is quite possible for an aspiring presidential candidate to have excellent policy ideas, and yet fail utterly to capture the imagination of the voters sufficiently to persuade them to vote for said candidate. Obviously, a certain sort of personality is needed to encourage people to give you their vote, but on top of this, especially with the Presidency, a candidate must persuade voters that she or he is a leader.
Leadership is one of those things that are difficult to define, but obvious when seen. It is sometimes confused with good management, yet the two are fundamentally different. In a discussion over Thanksgiving (and a good malt whisky) a good friend of mine and I decided that leadership is to management as vision is to strategy. This, while no doubt very profound (as such deep thoughts, spawned in a good malt, so often are) is still less than illuminating.
So, given this tricky issue, what sort of leadership do I see in the five Republican candidates that I am considering? Clearly Huckabee, Romney, and Guiliani all have governmental executive experience, having been either governor or mayor themselves. This is no small thing. In the last 40 years, only President George H. W. Bush (Bush the elder) has been elected President without having been a governor, and he had executive experience running the CIA. The fact that Guiliani has only been a mayor rather than a governor is irrelevant, given that he was mayor of New York, which has significantly more residents than either Arkansas or Massachusetts.
However, not having been a governor (or big city mayor) need not be a barrier to the Presidency (in spite of recent history). Clearly, the Democrats do not think so, since their last two Presidential nominees have not been governors, nor do any of their current front runners have gubernatorial experience. And certainly, John McCain's experience in the Hanoi Hilton was clear evidence of significant leadership under the most appalling conditions. Whether Fred Thompson has that leadership experience is less clear.
And yet, in these words I am making the same confusion between managerial skill and leadership as I warned against above. Leadership is something more than running a large organization, whether that be a state, one of the world's great cities, a major government bureaucracy, or a corporation. It is the ability to inspire people under the worst possible conditions. And that is why both McCain and Guiliani are such formidable candidates, because both have shown that ability to lead. McCain's demonstration was in the darkest of days, and was conducted under almost invisible conditions. Guiliani's leadership took place on the world stage, under the spotlight, and was singularly effective. Those who are now trying to attack Guiliani for his role as mayor in the aftermath of 9/11 are doing so because they recognize, whether explicitly or not, just how important and appealing the leadership he showed then is to the presidential race.
Clearly leadership is not the only desirable quality in a presidential candidate, nor do I wish to diminish the possible leadership qualities of Huckabee, Romney, and Thompson, but McCain and Guiliani are both very clearly leaders. Next November, that could be critical.