The standoff at the metal detectors was a characteristic stunt by Ms. Boebert. She is only 10 days into her term but has already arranged several episodes that showcased her brand of far-right defiance as a conspiracy theorist who proudly boasts of carrying her Glock handgun to Washington. She is only one of 435 House members, but Ms. Boebert, 34, represents an incoming faction of the party for whom breaking the rules — and gaining notoriety for doing it — is exactly the point.

In the same way Republicans leaders had to adapt to the Tea Party over a decade ago, House leaders must now contend with a narrow but increasingly clamorous element of the party that not only carries Mr. Trump’s anti-establishment message but connects with the voters who are so loyal to him — and so crucial to future elections…

“There is a trend, in both parties, of members who seem more interested in dunking on folks on social media and appearing on friendly cable networks than doing the work of legislating,” said Michael Steel, a Republican strategist and former press secretary for House Speaker John Boehner. “They seem to see public service as more performance art than a battle of policy ideas.”