As I’ve said before, this election isn’t going to be about sixth-year itches or any such electoral mumbo-jumbo. It’s going to be about presidential job approval, supplemented by the state of the economy (which also affects job approval to a degree) and how overexposed or underexposed the president’s party is. Right now, the second factor provides a drag beyond the president’s job approval, while the third factor will work heavily to Democrats’ advantage on Election Day.
With that said, the best midterm showing for the party of a president with a sub-45 percent job approval came in 1950, when the Democrats lost 11 percent of their caucus. This election occurred under fairly similar circumstances: Harry Truman was unpopular, but his party was well below the number of seats it typically held and the economy was growing.
It is still far too early to speculate about how many seats Democrats will lose (or perhaps gain) in the 2014 elections. But if Obama’s job approval is 40 percent on Election Day, gains would be unlikely, and Democratic losses in the low double digits — perhaps even as many as the 20 or so seats that would accompany losing 11 percent of their caucus, a la 1950 — would be plausible.
Of course, House seats don’t matter all that much, unless the president’s approvals stay at 40 percent through 2016 and a Republican president is elected. The big game is in the Senate. In 2014, there will be seven Democratic seats up for re-election in states that were more Republican than the country as a whole over the course of the last two presidential elections, according to Cook PVI.