Poll: Clinton, Sanders neck-and-neck in Iowa, NH

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Sen. Bernie SandersBernie SandersInterim DNC chair to impose 'tough standards' after email leaks Meet the rising Dem star positioned to help Clinton on gun control Sunday shows preview: Convention cleanup, Russian intrigue MORE (I-Vt.) has maintained his lead over Democratic presidential front-runner Hillary ClintonHillary Rodham ClintonTrump: Muslim soldier was a hero but his father 'has no right' to criticize me Interim DNC chair to impose 'tough standards' after email leaks Mark Cuban campaigns for Clinton in hometown of Pittsburgh MORE in New Hampshire and pulled to within the margin of error of her in Iowa, a new poll finds.

According to a NBC News-Wall Street Journal-Marist survey released on Sunday, Clinton has only a 3-point lead over Sanders in Iowa, well within the poll’s 4.8 percentage point margin of error. Clinton takes 48 percent support in the Hawkeye State, compared to 45 percent for Sanders.

That’s a much closer race in Iowa than other recent polls have found. According to the RealClearPolitics average of surveys, Clinton leads by 12.5 points in Iowa.

New Hampshire has long been a more competitive race between the two, and here the poll found Sanders leading with 50 percent of the support over Clinton at 46, in-line with other recent polling. According to the RCP average, Sanders leads by 5.3 points in the Granite State.

The Sanders campaign has been seeking to draw attention to polling that finds the Vermont senator performing better than Clinton in head-to-head match-ups against Republicans in the general election, and the NBC survey confirmed those claims.

Sanders leads GOP front-runner Donald TrumpDonald TrumpTrump: Muslim soldier was a hero but his father 'has no right' to criticize me Mother of soldier killed in Iraq: I was too 'in pain' to speak at convention Top Koch network adviser rejects Trump's talk of law and order MORE head-to-head by 13 in Iowa, while Clinton only leads him by 8. In New Hampshire the disparity is even greater, with Sanders leading Trump by 19, and Clinton only edging him by 1.

The poll produced similar findings in head-to-head match-ups against Sens. Ted CruzTed CruzHot air balloon crash kills 16 in Texas 100 days to go in volatile race Voting Trump because of the Supreme Court isn't enough MORE (R-Texas) and Marco RubioMarco RubioFlorida: 'High likelihood' of first Zika transmission in the US Overnight Healthcare: Rubio presses Obama to spend Zika money | FDA moves ahead with trans fat ban The Trail 2016: Her big night MORE (R-Fla.).

The most stunning finding was in New Hampshire, where Rubio leads Clinton 12, but trails Sanders by 9.

Sanders is buoyed in the head-to-head match-ups with Republicans by his strength among independents.

The survey of 2,821 registered voters in Iowa has a 1.8 percentage point margin of error. The survey of 1,888 registered voters in New Hampshire has a 2.3 percentage point margin of error. The surveys of 422 likely Democratic caucus-goers in Iowa and 425 likely Democratic primary voters in New Hampshire have 4.8 percentage point margins of error.

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