(Jenny Starrs/The Washington Post)

Republican female senators whose disapproval of the GOP health-care effort has at times endangered its progress are facing an increasingly pointed backlash from men in their party, including a handful of comments that invoked physical retaliation.

In the past week, Sen. Susan Collins (Maine) has been challenged by a male lawmaker to a duel. She and Sen. Lisa Murkowski (Alaska) were told that they and others deserve a physical reprimand for their decisions not to support Republican health-care proposals. Murkowski, who voted with Collins against starting the health-care debate this week, was specifically called out by President Trump on Twitter and told by a Cabinet official that Alaska could suffer for her choice, according to a colleague.

The language of retribution increasingly adopted by Republican men reflects Trump’s influence and underscores the challenges GOP women can face when opposing the consensus of their party, which remains dominated by men, outside experts said. A videotape of Trump surfaced during the campaign revealing him bragging in vulgar terms about groping women, and some believed that opened the gates for further insults and degrading behavior toward women.

“Masculine dominance in the Republican Party is not only in numbers but in culture,” said Kelly Dittmar, a scholar at the Center for American Women and Politics at Rutgers University and the author of “Navigating Gendered Terrain: Stereotypes and Strategy in Political Campaigns.”

“When the person who is supposed to be the leader of the party shows it’s okay to use those sorts of attacks, whether they are specifically gendered or not, that is something that catches on at other levels,” Dittmar said. “We see it in the [elected officials] who feel it’s okay to say things like this.”

President Trump, center, speaks as he meets with Republican senators on health care in the White House in Washington on June 27, 2017. Sen. Susan Collins (R-Maine), left, and Sen. Lisa Murkowski (R-Alaska) listen. (Susan Walsh/Associated Press)

Collins and Murkowski have been among the Senate’s most consistently skeptical voices as Republicans accelerate their effort to amend the 2010 Affordable Care Act (ACA). In contrast with conservative critics such as Sen. Rand Paul (R-Ky.), both women have criticized GOP health-care proposals because they would cut funding to Medicaid and Planned Parenthood, which provide medical care to hundreds of thousands of people in their states. Both have raised concerns about a lack of transparency in the crafting of GOP legislation.

They are not the only critics who have faced political attack over health-care legislation, but the backlash has not been as aggressive.

Notably, the pro-Trump political outfit America First Policies targeted Sen. Dean Heller (Nev.) with $1 million in TV and radio ads last month after he announced opposition to one ACA overhaul bill. The group canceled its campaign after senior Republicans intervened on Heller’s behalf.

Trump also has threatened electoral consequences against Republican senators who oppose the party consensus on health care. “Look, he wants to remain a senator, doesn’t he?” the president said recently of Heller, who was seated next to him at a lunch event. “I think the people of your state . . . [are] going to appreciate what you hopefully will do.”

Still, the most colorful and threatening comments have targeted Collins and Murkowski.

Rep. Blake Farenthold (Tex.), in an apparent reference to Collins, told a radio host Friday that if she were a “guy from south Texas, I might ask him to step outside and settle this Aaron Burr-style,” invoking the 1804 duel in which Alexander Hamilton was killed.

“Like the President, I am sick and tired of the left-wing biased media trying to make something out of nothing,” he said in a follow-up statement. “This was clearly tongue in cheek. That being said, I’m extremely frustrated with Senate Republicans who are breaking their promise to the American people to repeal and replace Obamacare.”

Collins was caught on a hot mic responding, when Sen. Jack Reed (D-R.I.) said she could beat Farenthold in such a duel. Collins called Fahrenthold “huge” and “extremely unattractive.” They later apologized to each other, CNN reported.

Rep. Earl L. “Buddy” Carter (R-Ga.) told MSNBC on Wednesday that someone should “go over there to that Senate and snatch a knot in their a--,” a regional phrase that refers to punishment, usually of disobedient children. MSNBC reporter Ali Velshi had asked Carter what he thought of Trump’s tweet chastising Murkowski for opposing the start of the health-care debate.

Carter later said the remark was directed at all those senators who, like Murkowski, stood in the way of easy victory for the legislation.

“Rep. Carter’s comment was in no way directed toward Senator Murkowski specifically,” Carter spokeswoman Mary Carpenter wrote in an email. “His words speak for themselves that he was not speaking about a single senator. This is a southern phrase used frequently throughout Rep. Carter’s lifetime which simply means get your act together.”

The comments are particularly poignant, given that Republican women in the Senate were excluded from the chamber’s original working group on health care.

“It’s too bad some folks are spending so much time creating cute catchy phrases in order to take potshots at colleagues,” Julie A. Conway, executive director of VIEW PAC, which recruits and trains Republican female candidates, wrote in an email.

“I wish they would spend as much time and energy sitting down with these women lawmakers to help find solutions and a strategy to get real health-care reform that Americans can feel good about.”

Dittmar argued that these kinds of comments undermine female leaders in the long run.

“The fact they call out specific women marks those women as outside of the norm. For those who may question women’s capacity to be just as qualified as elected officials, it mines that vein of doubt or underlying bias,” she said.

Trump’s rhetoric has been almost calm by comparison.

“Senator @lisamurkowski of the Great State of Alaska really let the Republicans, and our country, down yesterday. Too bad!” he tweeted Wednesday morning.

But later in the day, according to the Alaska Dispatch News, Interior Secretary Ryan Zinke called Murkowski and Sen. Dan Sullivan (R-Alaska) to say that Murkowski’s vote against opening the health-care debate could have repercussions for federal policy affecting Alaska.

“The message was pretty clear,” Sullivan told the news outlet.

The next day, a nominations markup in the Senate Energy and Natural Resources Committee was postponed, leading some observers to speculate that Murkowski — the panel’s chairman — had deferred it in retaliation for Zinke’s call. A spokeswoman for the committee told The Washington Post that the meeting was postponed because of the uncertainty of the Senate schedule.

Mike DeBonis contributed to this report.