A Ron Paul presidency would involve a bunch of executive orders firing 90% of government workers because he thinks their functions are unconstitutional, followed by a crisis and (successful) impeachment.
Of course, Paul's the only candidate where you'd have to imagine a very different political landscape for him to win. Palin would need a somewhat dumber, more rightwing country, but it'd still be recognizable as the US, whereas a President Paul fanfic would demand a lot of worldbuilding.