When a majority of House Republicans opposed a successful push by right-wing rebels to oust Speaker Kevin McCarthy last week, many warned that a leaderless House would be paralyzed to respond to a domestic or international crisis.

Days later, Hamas militants attacked Israel in a brazen assault, prompting Prime Minister Benjamin Netanyahu to declare, “We are at war.”

Now, Republicans are fuming at the rebels in their ranks for rendering Congress impotent and ineffectual at a time when legislation and additional funding could be needed to help one of America’s closest allies.

“It wasn’t my idea to oust the speaker, and I thought it was dangerous,” Representative Michael McCaul, Republican of Texas and chairman of the House Foreign Affairs Committee said Sunday on CNN. “I look at the world and all the threats that are out there. What kind of message are we sending to our adversaries when we can’t govern, when we’re dysfunctional, when we don’t even have a Speaker of the House?”

Representative Mike Lawler, Republican of New York, was even more direct, calling the removal of Mr. McCarthy “idiotic” and using a profanity to describe the “unmitigated” mess caused by Representative Matt Gaetz of Florida and the other Republican rebels who joined with Democrats to remove Mr. McCarthy.

“Uncertainty and chaos in the U.S. breeds vulnerability around the world,” Mr. Lawler wrote on the social media site X, formerly known as Twitter, on Saturday. “The House should immediately reinstate McCarthy and stop screwing around.”

Republicans were scrambling Sunday to determine who would become the next House speaker. Two leading candidates have emerged: Representative Steve Scalise of Louisiana, the No. 2 House Republican, and Representative Jim Jordan of Ohio, the Judiciary Committee chairman.

Both men are seen as more conservative than Mr. McCarthy. Mr. Jordan, a co-founder of the ultraconservative House Freedom Caucus, has the endorsement of former President Donald J. Trump.

On Fox News, Mr. Jordan said Sunday that his first move as speaker would be to help Israel.

“I want to give them what they need to win,” Mr. Jordan pledged on the show “Sunday Morning Futures.”

Mr. Scalise also pledged full support.

“Make no mistake: The United States will always stand with Israel, our greatest ally in the Middle East,” he wrote on social media. “They must defend themselves as their citizens are slaughtered by Hamas terrorists. They have our full support and our prayers.”

The United States already provides Israel more than $3 billion in military assistance every year, but the House would need to elect a new speaker should more funds be needed.

“There will likely be a need for some additional appropriations,” Representative Hakeem Jeffries of New York, the top Democrat in the House, said on CNN, adding, “Congress should certainly be prepared to do that sooner, rather than later.”

Mr. Jeffries urged House Republicans to agree on a speaker so that “we can move forward to get the business of the American people done” both domestically and in support of Israel.

Republicans plan to have a closed-door meeting Tuesday to hear from both candidates, with a floor vote expected on Wednesday. Aides have said the process could stretch out longer if Republicans fail to unite behind a candidate.

Throughout the weekend, some of Mr. McCarthy’s staff members posted on social media, criticizing the hard-right members who removed their boss from his position.

“Israel is at war,” Mr. McCarthy’s deputy spokesman, Chad Gilmartin, wrote on the X platform. “Americans have likely been killed and are being held hostage. Congress is essentially paralyzed without a House speaker.”

Mr. Gaetz, who led the rebellion against Mr. McCarthy, rejected the idea that he had caused chaos and paralysis endangering the United States and its allies. He said he remained undecided on whether to back Mr. Jordan or Mr. Scalise, but said he would support whichever candidate a majority of Republicans backed.

“I don’t think that other countries think about Kevin McCarthy’s speakership quite as much as Kevin McCarthy does,” Mr. Gaetz said on NBC’s “Meet the Press.” “We’ll have a new speaker next week, and we’ll be prepared to do our work.”