Never Trump Republicans have all but given up on mounting a serious primary challenge to President Trump in the aftermath of special counsel Robert Mueller's failure to find collusion between the Trump campaign and Russia.

“I think there’s broad consensus that no one is moving toward a run,” said Rob Stutzman, a Republican consultant in California who for several months has been involved in discussions about dislodging Trump.

Trump remains broadly popular with Republican voters, and one of the most formidable potential challengers, Maryland Gov. Larry Hogan, announced over the weekend he would forgo a 2020 bid.

Some Never Trump Republicans are even contemplating quietly redirecting their energy toward boosting Joe Biden, the front-runner for the Democratic nomination, saying this strategy might be their only viable option. Many Republicans uncomfortable with Trump view the former vice president, an old-school liberal, as an acceptable Democrat, at least compared to the modern liberals that comprise most of the rest of that party’s crowded field.

"Even if Mueller had obtained some sort of smoking gun, it probably still wouldn’t have moved [Trump's] base," conceded a Republican prominent in the Never Trump movement, who requested anonymity in order to speak candidly. "Trump is going to be the Republican nominee.”

That's the verdict Hogan arrived at, and it influenced his decision.

The only announced challenger, former Massachusetts Gov. Bill Weld, is not taken seriously. In hypothetical matchups, Trump trounces Weld, who is waging a shoestring campaign.

In a telephone interview, Hogan told the Washington Examiner that he received enthusiastic encouragement from Republican thinkers, donors, and elected officials impressed with his ability to connect with a broad cross-section of voters in deep blue Maryland. But after assessing the political atmosphere since the Russia investigation concluded and Mueller issued his report, Hogan determined the support that matters most was missing.

“There wasn’t a groundswell among the average Republican primary voter," he said. "They seem to be, at this point, very happy with the president.”

Former Ohio Gov. John Kasich is still a potential 2020 candidate, perhaps offering hope to Never Trump Republicans who have not completely abandoned searching for challengers with more promise than Weld.

But Kasich clearly has misgivings about going forward. A Republican primary candidate three years ago, he tweeted that “all of my options are on the table” immediately after suggesting in an interview on CNN, where he works as a contributor, that he was bowing out because “90% of the Republican Party supports” Trump. In a text message exchange, Kasich adviser John Weaver confirmed that the Trump antagonist had not removed himself from contention.

Sarah Longwell, among the few Never Trump Republicans who reject claims that fighting the president from inside the GOP is fruitless, said she is convinced “there’s a far better than even chance that more primary challengers get in.” Longwell, working with conservative writer Bill Kristol to pave the path for a Republican to primary Trump, said she never viewed the effort as Mueller report-or-bust.

“What — was he going to get frog-marched out of the White House?” Longwell said. “If it was a knockout blow, then everybody’s getting in. I certainly wasn’t anticipating that.”

Last fall, immediately following midterm elections that saw Democrats flip 40 seats and win control of the House of Representatives, Trump appeared weakened. Soon after, the president’s standing was undermined further during a record-long partial shutdown of the federal government that he instigated. That led some committed Never Trump Republicans to believe the president could be vulnerable to a primary challenge.

The Mueller report, they believed, might be the catalyst.

Politically, they believed it could strike a crushing blow against Trump, significantly diminishing his support with voters inside the party and spurring high-profile Republicans to risk running against him. Logistically, they presumed it would be made public sometime in the spring, as it was, just in time for a serious campaign to launch and begin building the necessary organization.

But now, no serious campaign seems likely.