President Trump’s antagonists inside the Republican Party now have a fallback plan to scuttle his re-election: using the 2020 primary fight as a bludgeon to inflict irreparable political damage on him in the November general election.

The "Never Trump" movement’s preferred strategy is to recruit a formidable Republican who might block the president’s renomination, or at least mount an aggressive challenge that presses him all the way to the convention in Charlotte set for late summer next year. Efforts are underway to woo Gov. Larry Hogan of Maryland and other top Republicans uneasy with Trump.

Short of that, key renegade Republicans are preparing to settle for Plan B: mortally wound him.

“The example of Pat Buchanan is certainly in the minds of many of us of a certain age; impossible to win, eminently possible to wound,” Rick Wilson, a Republican consultant and leading Trump foe, told the Washington Examiner.

Buchanan, now 80, is a conservative pundit and former White House adviser who challenged President George H.W. Bush in the 1992 GOP primary, foreshadowing the rise of Trump populism. Buchanan was a long shot from the outset and never seriously threatened Bush for the nomination. But his campaign proved a major irritant and is partly credited with weakening the incumbent and boosting the inevitable victor, Bill Clinton, in the general election.

In 2020, that is the sort of primary challenge some "Never Trump" Republicans envision pursuing against this president if their favored option — running a contender strong enough to win — doesn’t come to fruition. For Republicans committed to dislodging Trump at all costs, wounding him in a primary would be adequate. No president challenged for renomination in the modern era has won a second term.

“For a number of people I’ve spoken to, putting a torpedo into Trump’s operation would suffice for them — if they could mortally wound him in a primary,” said a Republican insider involved in the effort.

Outright defeating a sitting president in a primary is nearly impossible, and Trump’s intraparty opponents are realistic about their prospects.

[Opinion: Is Trump especially vulnerable to primary challenge?]

That is why the Republicans who would potentially wage the strongest campaign to dethrone Trump — Hogan, former Ohio Gov. John Kasich, Sen. Ben Sasse of Nebraska, and others — are waiting for special counsel Robert Mueller to complete a federal investigation into possible collusion with Russia by the president and his associates in 2016.

Multiple Republicans could run if the probe’s conclusions implicate or in some way severely harm Trump. Otherwise, most could sit on the sidelines, except for second-tier GOP challengers such as Bill Weld. The former Massachusetts governor, who in 2008 backed Democrat Barack Obama, launched a quixotic primary bid this month.

Hogan, re-elected as Maryland governor in impressive fashion last fall and the subject of an intense draft effort, is not interested in being Plan B's sacrificial lamb.

“I wouldn’t have any interest in running just to be tilting at windmills,” Hogan told the Washington Examiner. “I wouldn’t do it to try to hurt the president or to help somebody else win a general election.”