And then there were two.
With Democrat Tom Suozzi’s victory in a special House election in New York on Tuesday, the shrinking Republican majority in the House dwindled even further, leaving the G.O.P. able to afford only two defections from the party line on votes when all members are present.
That gives them almost no cushion to deal with the inevitable absences caused by illness, travel delays, weddings, funerals and unforeseen events that could keep Republicans away from the House floor for votes. It comes as Congress is facing a crush of issues, including early-March deadlines for funding the government and a pending emergency national security spending bill to send aid to Ukraine, Israel and other American allies.
It also gives each individual House Republican even more leverage over Speaker Mike Johnson, who is already struggling to steer his unmanageable majority.
“I would be constantly on defense, I would be trying to avoid defeats, and I would be very, very careful,” former Speaker Newt Gingrich said in an interview.
The dangers of the slim margin were already apparent on Tuesday night, even before Mr. Suozzi won the Long Island seat formerly occupied by George Santos, the Republican lawmaker who was expelled from the House in December.
In their second attempt to impeach Alejandro N. Mayorkas, the homeland security secretary, Republicans succeeded by just one vote after three of their members broke with the party to oppose it. If either of the two Democrats who were absent had shown up, the impeachment that Republicans had been promising their voters for more than a year would have failed again. (The two Democratic absentees were Representative Judy Chu of California, who said she was isolating after testing positive for the coronavirus, and Representative Lois Frankel of Florida, who was grounded by a delayed flight.)
“That impeachment resolution could not pass now,” said Aaron Fritschner, a longtime adviser to Representative Don Beyer, Democrat of Virginia, who said Mr. Suozzi’s seat flip “imperils both Republicans’ ability to hold the House in November and their ability to govern until then.”
“Under Republican control, the House has seen historic amounts of chaos and paralysis, and it’s about to get a little bit crazier,” Mr. Fritschner added.
After Mr. Suozzi is sworn in, Republicans will hold 219 seats to Democrats’ 213, down three from when they won a narrow majority in November 2022, because of a combination of coincidence, scandal, health issues and political turmoil.
On Wednesday, as they watched their majority get even smaller, some Republicans were ruing the decision by their colleagues to expel Mr. Santos, who served as a reliable Republican vote in Congress despite being a serial fabulist, a figure of national ridicule and the subject of a 23-count federal indictment.
Representative Byron Donalds, Republican of Florida, told CNN that Mr. Santos had yet to be found guilty of any crimes when he was expelled and, “to pre-empt that, to score political points, was stupid.”
The minuscule majority will be Speaker Mike Johnson’s reality for the coming year. In April, Democrats are likely to fill a safe seat that was occupied by Representative Brian Higgins, Democrat of New York, who left Congress earlier this month to become president of the Shea Performing Arts Center. That seat won’t change the margin of control, but will allow even less room for Republican absences.
There will be some modest relief for Republicans in the late spring and early summer, when they are likely to fill two safe seats that were vacated by Representative Bill Johnson, Republican of Ohio, who left Congress to become the president of Youngstown State University; and former Representative Kevin McCarthy, who resigned from his California seat at the end of last year after being ousted from the speakership.
But with a Republican conference that is more often divided against itself than acting as a united front, it will remain difficult for Mr. Johnson to pass any bills that rely strictly on votes from his own party.
Mr. Gingrich said the only way forward for Mr. Johnson was to vastly lower expectations of what House Republicans could be expected to accomplish.
“Johnson has to sell the country that having House Republicans who use the investigative tool, and who block bad ideas, is all you can get until the election,” he said. “And then we’ll see if we have a better future. He shouldn’t exhaust himself trying to do things he can’t do.”
Vin Weber, a former Republican congressman from Minnesota, said the G.O.P. had made a bad situation worse because of its deep internal divisions.
“At the beginning of this Congress, you could have imagined the tightness of the margins would make Republicans band together,” Mr. Weber said. Instead, he said, the slim majority had emboldened the hard right to stage internal rebellions to press its own agenda, rather than falling in line to help the party put up a united front against President Biden and Democrats.
Mr. Johnson, like Mr. McCarthy before him, has responded by finding ways to steer around right-wing rebels and work with Democrats to pass critical measures. Mr. Johnson has done so recently by relying on a procedural motion that allows him to temporarily suspend House rules and speed legislation through but requires a two-thirds majority for passage.
Mr. Johnson has acknowledged the constricting reality of wielding such a fragile majority.
“We deal with the numbers we have,” he said on CBS’s “Face the Nation.”
But as his first, failed attempt to impeach Mr. Mayorkas showed in a humiliating fashion, with inevitable absences, he will not always know what numbers he has to deal with.
House Republican leaders have stepped up their efforts to keep tabs on their members’ whereabouts, but that can sometimes be like herding cats. Lawmakers often travel without letting leaders know of their plans, despite a requirement to give notice when possible. Sometimes a leader learns of a lawmaker’s location only when he or she posts a video or a photograph on social media.
“Illnesses, funerals, weddings — all of those things need to be taken into account in a way that they weren’t before,” Mr. Weber said. “Members are not used to having to be accountable for their whereabouts at all times. The House of Representatives is very much a group of individual entrepreneurs. They do not like to have to tell anybody where they’re going to be and when they’re going to be there.”
On big votes, members said, it is now understood that everyone will be present unless they have given notice that they cannot be there. On Tuesday, for instance, Representative Brian Mast, Republican of Florida, notified leaders that his flight was delayed and that he would not make the vote.
For Republicans, it was uncomfortably close.
“Thankfully, despite mechanical failures on my flight, we still had enough votes to impeach him tonight,” Mr. Mast posted on social media after the vote against Mr. Mayorkas.