Nixon or Obama; Who's the biggest fraud?

How can anybody rate Senator Obama before he is a President and compare him to a President who has already been adequately described by historians? Now, if you want to compare Bush and Nixon, that is easy. Both would be rated as egotistical, self-serving, evil men, but Bush is responsible for thousands of deaths and that makes him the worst. After Obama has been President for four years, we can get back to this.