The Mood in the Capitol Was Already Dark. Then Came Omicron.

(Ms. Greene’s father built a significant Atlanta-area building company before selling it to his daughter and son-in-law, while Mr. Clyde’s hulking gun shop, Clyde Armory, has kept him flush. They have already absorbed more than $100,000 in fines for their mask strike.)

Speaking just outside the chamber with his mask off, Representative Lee Zeldin, Republican of New York, was nonchalant. Omicron is mild, he said, and the steep rise in cases, in his home county on Long Island and across the country, will be followed by an equally steep decline.

“Those who are testing positive include the vaccinated and the unvaccinated, but for those I speak to — and there are many who have tested positive in recent weeks — fortunately for them, every single person I’ve spoken to has had a much milder experience than what was experienced in past variants,” said Mr. Zeldin, who is running for governor of New York.

Democrats tend to be a little less sanguine. Signs posted throughout the House proclaim in all capital letters “USE OF FACE COVERINGS REQUIRED,” but they appear to have only made the defiant dig in.

“That kind of defiance, we see it all across the board here,” said Representative James E. Clyburn of South Carolina, the Democratic whip, who missed his granddaughter’s wedding last month as he battled Covid. “And these are people who I hope will be able to survive whatever comes their way.”

The procedural machinations around voting rights legislation and the hand-wringing over President Biden’s social safety net and climate change bill can seem a bit beside the point when cases are soaring, hospitalizations nationwide are up 84 percent over the past two weeks and the average number of deaths now exceeds 1,700 a day.

Behind those marquee issues, the pandemic is again rising as a political focus. House Democrats on Wednesday rushed out new legislation to provide free at-home coronavirus tests while Senator Bernie Sanders, independent of Vermont, reintroduced his bill to send N95 masks to every home.