Why would any pro-Trump Republican official be worried about a challenge from Jeff Flake? Or John Kasich?

The South Carolina Republican Party is considering canceling its 2020 primary to discourage any challengers to Donald Trump.

Washington Examiner:

Drew McKissick, chairman of the South Carolina GOP, said he doesn't anticipate Trump would face a primary challenge and emphasized that the state party executive committee hasn't held any formal discussions about the contest, dubbed "first in the South" and usually third on the presidential nominating calendar. But McKissick would pointedly not rule out canceling the primary, indicating that that would be his preference. "We have complete autonomy and flexibility in either direction," McKissick told the Washington Examiner on Tuesday. "Considering the fact that the entire party supports the president, we'll end up doing what's in the president's best interest."

Perhaps it has more to do with history than any concern that Trump would be seriously challenged.

As Trump's re-election campaign ramps up, one component of the effort is preparing for possible primary challenges. The president is solid with Republican voters and would almost certainly defeat any intraparty opposition. But incumbent presidents who faced primaries are in greater peril in the general election, a fact not lost on the Trump campaign and the GOP more broadly. To minimize potential political hurdles for Trump, some state parties could move to scrap their 2020 presidential primaries. Already a long shot, the unavailability of one or more high-profile primary contests could further hamstring the odds of any Republican who dares to run against Trump in 2020. There is precedent for this strategy, even when less uncertainty has swirled around the incumbent president. In 1992, the Iowa GOP didn't issue a presidential ballot during its caucus, to save President George H.W. Bush from being embarrassed by Pat Buchanan – Bush won the New Hampshire primary, although Buchanan still did better than Bush had hoped. In 2004, when President George W. Bush was running for re-election, the South Carolina GOP skipped its presidential primary.

Trump is not a Bush, and Kasich and Flake certainly aren't Pat Buchanan clones. The NeverTrumps are dead and buried, never to rise again. The prospect of any Republican getting more than a handful of delegates is remote.

Any challenge to Trump might make him appear weak in some respects. But the wisdom of canceling a primary in favor of a caucus escapes me. Challengers have a much better shot at making a splash in a caucus state than a primary. Bernie Sanders became a viable candidate when Hillary Clinton ignored the caucus states, allowing Sanders to use the enthusiasm of his supporters to overwhelm Clinton forces in a dozen caucus states.

But the prospect of impeachment might make a challenger appear more viable. It would still be a long-shot bid, but another candidate would give GOP voters an option – something the Trump campaign may want to avoid if the president is threatened with impeachment.

At this point, it's Trump's race to lose. It's hard to see anyone in the party who would disagree with that.