So much for all the talk about a GOP challenge to President Trump.

Trump crushes his potential Republican opponents in head-to-head matchups in New Hampshire, and the president’s loyal followers aren’t wavering despite an onslaught of media attacks, a new poll shows.

Ohio Gov. John Kasich, who recently traveled to New Hampshire to test the waters, gets toasted by Trump in a 68-23 percent blowout among Republican voters in the first-in-the-nation primary state. And it’s worse for Jeff Flake. The Arizona senator falls by a 72-15 percent margin, according to the Suffolk University poll.

Even poor Mitt Romney, who is currently scrambling to head off a conservative challenge in the Utah Senate race, has been abandoned by New Hampshire voters, who overwhelmingly side with Trump in a head-to-head matchup.

In fact, it seems all the talk about Russian collusion and impeachment hasn’t dented Trump much at all.

His numbers among all voters are roughly the same as when he took office: 41 percent favorable, 53 percent unfavorable.

“I don’t think they’re bad numbers,” says Suffolk University pollster David Paleologos. “They reaffirm his strength in the Republican Party and his appeal among his core supporters.”

The poll did not measure Trump’s strength against Democratic opponents, but it’s likely that in 2020 New Hampshire will once again be a key swing state, with Trump remaining competitive.

And the president isn’t hurting other Republicans like many Democrats hope he will. GOP Gov. Chris Sununu is relatively popular in the Granite State, and holds more than 20-point leads over his Democratic challengers.

The Suffolk poll of 315 Republican primary voters, conducted last week, has a plus or minus margin of 5.5 percent.

On the Democratic side, there’s bad news for U.S. Sen. Elizabeth Warren. She’s ahead.

Warren gets nearly 26 percent support among 295 Democratic primary voters, with former Vice President Joe Biden in second place at 20 percent.

That’s bad for Warren because early front-runners never win in New Hampshire. Just ask Hillary Clinton.

Warren, in fact, should be ahead by an even bigger margin. She’s from neighboring Massachusetts, and liberals have been clamoring for her to run for years.

The Democrats to watch are further down in the polling numbers. Former Massachusetts Gov. Deval Patrick, who has been out of the public eye for several years, still gets 8 percent support in a field that doesn’t include Warren. New Jersey Sen. Cory Booker gets 10 percent in a Democratic trial heat without Warren in the mix.

The real loser in this poll is Bernie. Vermont Sen. Bernie Sanders, who destroyed Hillary Clinton in the 2016 New Hampshire primary, is down at just 13 percent in a trial heat that includes Warren. Even in a field without Warren, Sanders is behind Biden.

Paleologos calls Biden the “safe and steady” choice. But that may not be enough in 2020.