John Kasich. AP Photo/Carolyn Kaster More Republican voters in New Hampshire would support Ohio Gov. John Kasich than would support President Donald Trump in a 2020 presidential primary race, according to a new poll.

The survey, called the New Hampshire Poll, found that, overall, 52% of likely GOP primary voters would support Kasich, a vocal Trump critic who ran as a more moderate Republican in the 2016 presidential election, while just 40% would cast their ballots for Trump.

Among undeclared voters, 54% would vote for Kasich and 37% for Trump. A majority — 53% — of all of the surveyed GOP voters said they disapprove of Trump's job in office, while just 44% approve.

A plurality of voters also said they would support Kasich's candidacy over that of Vice President Mike Pence. Forty-one percent said they would vote for the governor, while just 27% said they would vote for Pence.

Kasich, who was the last primary competitor to drop out of the 2016 race before Trump took the party's nomination, has not ruled out the possibility that he'll run in 2020. The governor, whose term will be up in January 2019, spent the spring touring the country promoting his new book, "Two Paths: America Divided or United," and has planned several policy forums in Ohio and across the country.

For his part, Pence has vigorously denied having any ambition to run for president in 2020, despite speculation among fellow Republicans that the vice president is positioning himself for a run.

But mounting a primary challenge to a sitting president is a risky move — no president in American history has lost to a challenger within his own party.

The survey of 600 likely Republican presidential primary voters was conducted between August 4 and 6 and had a margin of error of plus or minus four percentage points.