The Republican allies of former President Donald J. Trump wasted no time in blasting the guilty verdict returned by a New York jury on Thursday and in imploring him to appeal, repeatedly turning to words like “travesty” and “injustice” to describe the moment.

Top Republicans on Capitol Hill tried to one-up one another in demonstrating who could defend Mr. Trump, who was convicted of all 34 felony counts in the hush-money case, and condemn the verdict in the most strident terms.

House Speaker Mike Johnson, who was among the cavalcade of Trump supporters who showed up outside Mr. Trump’s trial in a show of loyalty, called Thursday a “shameful day in American history.”

“Democrats cheered as they convicted the leader of the opposing party on ridiculous charges,” he said. “This was a purely political exercise, not a legal one.”

The No. 2 Republican in the House, Steve Scalise of Louisiana, said in a statement that America had been rendered a “banana republic.” And Representative Jim Jordan of Ohio, the chair of the House Judiciary Committee and a close ally of Mr. Trump’s, condemned a “kangaroo court.”

“The verdict is a travesty of justice,” he fumed.

It was also a moment of alignment for Republicans who have at times been at cross purposes, like Representative Matt Gaetz of Florida, another Trump acolyte, and Kevin McCarthy, the former House speaker Mr. Gaetz and other hard right members pushed out last year.

Mr. McCarthy, whose differences with Mr. Trump had simmered in the open, wrote that “President Trump’s only ‘crime’ is running against Joe Biden in 2024.”

Mr. Gaetz leaned into the moment to help Mr. Trump raise money for his presidential campaign, sharing an image on X of Mr. Trump pumping his fist with the words “never surrender” in all caps.

And Vivek Ramaswamy, one of Mr. Trump’s former G.O.P. primary opponents, warned on X: “This will backfire.”

The sentiment was echoed by the right-wing podcaster Jack Posobiec, who declared matter-of-factly: “Trump just won the election.”

Still, some prominent Republicans called for respecting the judicial system.

“Regardless of the result, I urge all Americans to respect the verdict and the legal process,” Larry Hogan, the former governor of Maryland who is running for Senate there, said in a statement. “At this dangerously divided moment in our history, all leaders — regardless of party — must not pour fuel on the fire with more toxic partisanship. We must reaffirm what has made this nation great: the rule of law.”

Chris LaCivita, a top official in the Trump campaign, responded to Mr. Hogan online: “You just ended your campaign.”

John R. Bolton, who fervently disavowed Mr. Trump after serving as his national security adviser, urged Republicans to abandon the former president.

“Today’s verdict is a fire-bell in the night,” Mr. Bolton wrote on X. “The Republican Party now has one last chance to change course, and not nominate a convicted felon for President.”

Senator Tim Scott of South Carolina and Gov. Doug Burgum of North Dakota, two of Mr. Trump’s former primary rivals who have since become loyal surrogates, also weighed in. Mr. Scott called the process a sham in a video posted on social media. “Un-freaking-believable,” he said. And Mr. Burgum, whose presidential bid never gained traction, wrote on X that “This lawfare should scare every American.”

Representative Lauren Boebert, the provocateur from Colorado, wrote, “If this were happening in another country, Biden would be asking Congress to authorize a war to reinstate democracy abroad.”

Kari Lake, a candidate for the Senate in Arizona and one of Mr. Trump’s fiercest defenders, called the verdict an “egregious example of election interference and an outright mockery of the rule of law.”

“This legal tyranny will be summarily rejected by the American people on Nov. 5,” she wrote.

Mike Pompeo, who was secretary of state under Mr. Trump and whose name has been floated as a potential running mate, panned the jury’s verdict.

“The future of this country should — and will — be decided by the American people in an election, not by 12 New Yorkers in a travesty of a politicized courtroom,” Mr. Pompeo wrote on X.

Ken Bensinger contributed reporting.