No matter who captures the Democratic nomination, that candidate will have to contend with voters’ impressions of President Obama. And in New Hampshire and Iowa, two states solidly in the swing column, Obama’s approval ratings are worryingly low.

Just 43 percent of New Hampshire voters say they approve of the job Obama is doing, while 56 percent disapprove. In Iowa, 43 percent approve and 54 percent disapprove.

Only once in modern political history has a party won control of the White House in three consecutive elections, when George H.W. Bush won election after Ronald Reagan’s two terms. Even with an overwhelmingly popular Bill Clinton, whose approval rating stood at 57 percent in a Gallup survey taken just before Election Day 2000, Democratic nominee Al Gore just barely missed winning the White House.