Gandalf for President? Surely not? He's a committed smoker! Isn't that equal to being Evil McEvil in the USA these days?
I think you'd be more likely to see
Legolas as President with his clean livin' ways
But seriously, Formendacil was onto something suggesting Gandalf as a civil servant. He wouldn't make a good Sir Humphrey or another kind of permanent civil servant (not serpentine enough), but he would make a superb private secretary or adviser, the kind of person drafted in by a Minister to act independently of the civil service and the party (some call them spin doctors but they're not all like Alastair Campbell!). I think I've mentioned this before, but the role he plays for Aragorn is very much in this line - you particularly see it in the council after the Battle of the Pelennor Fields.