Story highlights Hillary Clinton leads Bernie Sanders in Iowa, 48% to 45%, among likely caucus-goers, a new poll shows

Sanders is ahead in New Hampshire, 50% to 46%

Washington (CNN) 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.

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