Washington (CNN) A majority of Democratic voters say Hillary Clinton is their top choice in the race for their party's nomination, but her margin over Bernie Sanders is smaller than it has been at any point since before the field narrowed to three.

According to a new nationwide CNN/ORC Poll, Clinton tops Sanders 52% to 38% among registered voters who are Democrats and Democratic-leaning independents. Former Maryland Gov. Martin O'Malley is far behind the two top candidates at just 2%.





Full results: CNN/ORC poll Though Clinton's lead over Sanders remains in double-digits, these figures represent the tightest the contest has been since early September. Back then, before Vice President Joe Biden had opted out of the race and before the remaining Democratic field ever took to a debate stage, Clinton topped Sanders by just 10 points.

The poll findings come as the three remaining Democratic candidates prepare to make their final pitches to Iowa voters in a town hall set to air on CNN Monday night.

Though the national picture tilts in Clinton's direction, according to this poll, other recent surveys in Iowa and New Hampshire -- the two states hosting the first contests of the 2016 nomination battle -- suggest Clinton will face an uphill climb in trying to grab an early victory. Iowa polls find the top two Democrats near-even among that state's likely caucus-goers, while Sanders has something of a home-field advantage in New Hampshire and tops Clinton there handily.

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