I look for a Machiavellian president. Someone who is willing to violate morality in order to achieve a moral goal.
I'm going to just put probably the three best presidents on the table.
Theodore Roosevelt for example faced the rise of fascism. After pearl harbor he said that most U.S. forces would be concentrated on Japan when he did the exact opposite. He sent them to Europe to fight Germany which was a bigger threat. He wire tapped phones without warrants, and even went through peoples mail. A direct violation of civil liberties to achieve a moral goal.
Ronald Reagan is a good example. Who violated the law by arming rebels in several third world countries to overthrow the potential governments that could provide a foothold for the evil regime of the Soviet Union. When he was caught and put on congressional trial, he lied.
It's these kinds of people who get things done. They realize what's important and are willing to see the greater good.