Poll: Democratic 2016 race narrows in Iowa

Bernie Sanders has nearly caught Hillary Clinton in Iowa's Democratic presidential race and remains ahead of Clinton in New Hampshire, a new poll shows.

Clinton holds a 48% to 45% lead over Sanders among likely caucus-goers -- a smaller lead than other polls have shown her with for months in the Hawkeye State -- according to a NBC News/Wall Street Journal/Marist poll released Sunday morning.

And Sanders is ahead, 50% to 46%, among likely New Hampshire primary voters -- maintaining his edge in what's long looked like the early-voting state in which the Vermont senator has the best shot of defeating Clinton.

The polls also show that Sanders performs better in head-to-head matchups with Republicans Ted Cruz, Donald Trump and Marco Rubio than Clinton does, giving his campaign ammunition to rebut Clinton's argument that she is more electable in a general election.

The numbers raise the possibility that Clinton, despite her national front-runner status, could lose one or both of the first two states to vote in the nominating process.

Clinton herself has noted the damage such losses can do, telling supporters in a fundraising email Saturday (designed in part to instill a sense of urgency in Clinton's supporters) that losing New Hampshire "could be a sharp blow to all the work we've done."

On the Republican side, Texas Sen. Ted Cruz remains the front-runner in Iowa -- but it's a narrow lead, at 28% to Donald Trump's 24%. The two are trailed by Florida Sen. Marco Rubio at 13% and Ben Carson at 11%, with no other candidates topping 5%.

In New Hampshire, Trump leads with 30% support -- more than double any other candidate's backing.

In second is Rubio at 14%. He's followed by New Jersey Gov. Chris Christie at 12%, Cruz at 10%, and Ohio Gov. John Kasich and former Florida Gov. Jeb Bush at 9% each.