The president may well win reelection, but there’s little question he hasn’t had the same kind of top-of-the-ticket pull demonstrated four years ago.

Unlike in 2008, when Barack Obama’s national numbers helped lift up Democratic congressional candidates across the map, the president has had far less impact this time around. And for the Democrats in conservative districts in the South and Rust Belt, Obama’s presence on the ballot has been more hurt than help.

That dynamic, perhaps more than any other, Democrats say, kept them from stirring up the kind of wave conditions they needed to stage a House takeover this year. Races that would have drifted in the Democrats’ direction four years ago required far more of a push this time.

“There was a wave that was supporting us in many different ways in 2008, and obviously this was a very different election,” said Paul Maslin, a Democratic pollster.

Obama’s poor first debate performance also caused a downdraft for vulnerable House Democrats.