Nate Silver calls the relationship between unemployment numbers and the presidential election "maddeningly inexact." Silver emphasizes that a weaker economy will definitely hurt Obama. But:
Unemployment increased by 1.9 percentage points over the course of Richard Nixon’s first term, but he won re-election overwhelmingly. It also increased during George W. Bush’s and Dwight D. Eisenhower’s first terms, and their re-election bids were also successful. The unemployment rate fell to 3.9 percent from 5.3 percent, meanwhile, during Bill Clinton’s second term — but his Vice President, Al Gore, could not beat Mr. Bush in the Electoral College.
The Dish 