[Gwathagor]

Hmmm.

The Istari were strictly forbidden to govern or rule over the Children of Illuvatar, and so the holding of a political office such as the presidency would be out of the question for a dutiful wizard like Gandalf. He would probably turn down the presidency if we offered it to him. However, the fact that he would have no aspirations to political power would make him the only safe candidate, as most politicians are exactly the opposite. Because of his unwillingness to play the politics game, and because of his lack of interest in power, he would likely not be elected.

But, if the impossible happened, and Gandalf not only was elected but accepted the presidency, I have no doubt that he would be a wise and just leader.

On another note, P.J.'s team must have seen something of Churchill's position and policies in Gandalf as well, given the wizard's near direct quoting of Winston at the end of TTT (albeit with the locations changed).