“To devolve into childish name-calling usually doesn’t win the argument. I think we can do better,” said Tom Rooney, a former five-term Republican representative from Florida. “Maybe this is what the donors to the N.R.C.C. want to hear nowadays. Maybe name-calling raises money, and that’s what we’ve become.”

For the communications arm of the committee, that has translated into circulating photographs depicting Representative Adam B. Schiff of California, the chairman of the House Intelligence Committee, as a clown and barraging reporters with statements reminding them of the nicknames with which they refer to Democratic lawmakers and candidates. Some are just referred to as “socialist losers”; others have been given their own bespoke tags.

Ms. Underwood, Democrat of Illinois, is “Fake Nurse Lauren.” (Ms. Underwood, who earned a bachelor’s degree in nursing from the University of Michigan and worked as a research nurse, never worked specifically with patients.) Representative Collin C. Peterson, Democrat of Minnesota, is “Cranky Collin.”

Ms. McBath, who represents Georgia’s Sixth District, has become a particular target for the committee. During the campaign, she said she briefly moved to Tennessee to help her husband work through family issues, then switched her residency back to Georgia. Claiming that she is not a resident of Georgia, the committee sent a gift basket to the Tennessee home of her husband. Fox News, obtaining a copy of the signature, wrote an article featuring a comment from the House Republican campaign arm that reiterated that Ms. McBath is a resident of Tennessee. But a close look at the signature showed that her mother-in-law — “M McBath” — signed for the package — a fact mocked by The Atlanta Journal-Constitution.

Committee officials show no sign of tempering their attacks.

“We make no apologies for aggressively calling out the anti-Semitic racists in the socialist Democratic Party totally consumed by their hatred of President Trump and America,” Chris Pack, the communications director of the campaign arm, said in a statement.