Maybe we need somebody who not only knows good choices from bad ones, but who knows it from hard-won experience: somebody who, instead of parroting wisdom about not being goaded into unnecessary conflicts, learned that lesson first-hand. But also somebody who’s seen what happens when the wrong man gets power; and who then worked to remedy that, for a reason. So, a guy who’ll make the right call in office: maybe not the first time, but whenever he gets a second chance.
McFly/Brown 2020!
Jeff Tracy, astronaut, head of International Rescue. In a crisis there is simply no one more level headed or capable.
If 9/11 happened on his watch he probably would have had rocket interceptors able to force an airliner to a safe landing, at least to protect key spots like the Pentagon. If the World Trade Center was hit, even if he couldn’t prevent them from falling everyone would have gotten out safely that didn’t die in the initial impact. And they would have been rebuilt by the end of his first term, a mile high and probably doubling the energy supply for the city. Forget about the wars that followed, there’s a certain Lady friend of his that no criminal mastermind would escape.
Hurricane Catrina would be known as a model for prompt government action in evacuating a major city and emergency flood measures that prevented untold amounts of property damage.
I expect he would be just as good in a financial meltdown or missile crisis.
The entire countries infrastructure would be improved to be faster, more efficient, and far safer. Although, there will be more buildings sliding over and things popping up out of the ground then you are used to.
I like the Jeff Tracy nomination. 
I’d like to throw John Sheridan’s hat into the ring.
Gunnery Sergeant Hartman.