Donald Trump has a commanding double-digit lead over his primary challengers in New Hampshire and Nikki Haley is gaining momentum, a CNN poll found. 

42% of Republican primary voters back Trump, followed by 20% for Haley, the poll found.

It's more good news for Trump just a couple of months out from the New Hampshire primary, which falls on January 23.

Trump leads in NH

The poll was also sobering for Ron DeSantis, once hailed as Trump's biggest primary threat.

The Florida gov slid to fourth place with 9% supporting him - behind Trump, Haley, and even former New Jersey governor Chris Christie, an unpopular figure among Republican voters and a fierce Trump critic. Christie came in third with 14%, while Vivek Ramaswamy came in fifth with 8%.

55% of registered Republicans back Trump, followed by 17% for Haley and 11% for DeSantis. Undeclared voters, who do not belong to a party but say they are likely to vote in the GOP primary, are divided between Haley (25%), Trump (24%) and Christie (24%).

The CNN poll was taken from November 10-14 by the University of New Hampshire Survey Center, with a sample of 1,946 adults and a margin of error of 2.2%.

57% said Trump is the most likely to defeat President Biden in 2024, despite claims from Trump's rivals that he is "unelectable."

The biggest movement in the poll was an eight-point boost for Nikki Haley, whose slick debate performances have received praise.

Trump gaining

Haley has been gaining in the polls, while DeSantis has been trending downward, opening up a vicious battle between the two for second place.

The New Hampshire primary will take place eight days after the Iowa caucus, which falls on January 15.

A fresh poll in Iowa has Trump taking the lead with 54% saying he is their first choice. DeSantis, despite an endorsement from Iowa Governor Kim Reynolds, came in second with 18%, followed by Haley at 12%, Ramaswamy at 6% and Christie at 3%.

A number of candidates have suspended their campaigns including former Vice President Mike Pence and Tim Scott, narrowing the field to Trump, Haley, DeSantis, Christie, and Ramaswamy.

Trump's dominance has led many to predict he will win the primary easily and go on to a rematch with President Biden in the general election next year.

Trump has overtaken Biden in recent polls, leading to considerable anxiety on the left about Biden's re-election prospects.