They’ve called the testimony “secondhand information” and “hearsay.” They’ve defended the president’s right to investigate corruption abroad. They’ve raised questions about the anonymous whistleblower who started the probe. They’ve argued that nothing ultimately happened. And, over and over, they’ve attacked the process.

Republicans battling the potential impeachment of President Trump have flitted among a multitude of shifting — and, at times, contradictory — defenses and deflections as they seek to cast doubt on a narrative supported by mounting evidence: that Trump subverted U.S. foreign policy to further his personal aims by pressuring Ukraine to launch politically motivated investigations, using hundreds of millions of dollars in military aid as leverage.

While those attacks — at least 22, according to a Washington Post tally — have done little to undermine the core allegations under investigation in the House, they have been remarkably successful in one respect: keeping congressional Republicans united against impeachment as the GOP casts the probe as partisan.

“Different people have different issues,” said Rep. Mark Meadows (R-N.C.). “One might have problems with the process. One has problems with the underlying facts. Some people say, ‘Well, gosh, I don’t agree with the phone call, but it’s not impeachable.’ So you get all kinds of different paradigms that it’s being viewed through. . . . Everybody will gravitate to their strongest argument that they feel most comfortable with.”

That dynamic has been on full display in recent days. Last week, faced with detailed testimony from three career State Department officials, Trump’s allies focused on dismissing the evidence as “hearsay” incapable of corroborating the core Democratic claim that Trump personally tried to withhold aid to force the investigations.

But when a political adviser at the U.S. Embassy in Kyiv, the Ukrainian capital, told impeachment investigators Friday that he overheard Trump ask about the status of the Ukraine investigations, Republicans’ definition of “hearsay” appeared to shift: Meadows, for instance, suggested that the witness, David Holmes, may have not heard the full context of the conversation and that it was not actually a firsthand account, since he was not speaking directly with the president.

Those arguments, meanwhile, have shared the stage with many others. During his opening statement at a hearing Tuesday morning, Rep. Devin Nunes (R-Calif.) launched a furious attack on the media, calling the impeachment inquiry a “fevered rush to tarnish and remove a president who refuses to pretend that the media are something different than what they really are — puppets of the Democratic Party.”

He went on to question why Democrats abandoned their plans to summon testimony from the whistleblower — without mentioning that virtually every major allegation in his Aug. 12 complaint has now been corroborated by congressional testimony.

Last week, a key GOP message suggested that because Trump ultimately lifted the hold on aid to Ukraine, there was, in fact, no wrongdoing — what some on Capitol Hill have called the “no harm, no foul” defense. An even older argument — that judging Trump’s behavior is best left up to voters in an election less than a year away — has also gained significant traction.

House Speaker Nancy Pelosi (D-Calif.) was personally compelled to rebut those arguments in a letter to her Democratic rank-and-file Monday, noting that Trump released the aid on Sept. 11, two days after the inspector general for the intelligence community notified Congress of the existence of a credible whistleblower complaint.

“There are also some who say that no serious wrongdoing was committed, because the military assistance to Ukraine was eventually released,” she wrote. “The fact is, the aid was only released after the whistleblower exposed the truth of the president’s extortion and bribery, and the House launched a formal investigation.”

Leaving the decision on Trump to voters would be “dangerous,” she added, “because the President is jeopardizing the integrity of the 2020 elections.”

Democrats say the expanding list of Republican arguments against impeachment reflects a flailing party that cannot rebut the central allegations at stake.

“The president of the United States attempted to bribe the Ukrainians into opening a phony investigation against his opponent and held up military aid to them as leverage — those facts are really not in dispute, and so they’re engaged in an effort to distract from that,” said Rep. David N. Cicilline (D-R.I.). “I think the American people are seeing it for what it is, and I think it’s very sad.”

Despite Democrats’ confidence in the strength of their case against Trump, however, there has been remarkable unity in the ranks of Republican lawmakers. No Republicans joined Democrats, for instance, in an Oct. 31 vote formalizing rules for the impeachment inquiry, though one ex-Republican, Rep. Justin Amash (I-Mich.), voted yes.

Rep. Tom Cole (R-Okla.) said that dynamic was unlikely to change anytime soon, thanks to what he called a strategic misstep by Democrats — choosing not to follow the lengthy processes in the impeachment investigations of Presidents Richard M. Nixon and Bill Clinton.

In those cases, months-long investigations — public and private — preceded formal House impeachment proceedings.

Independent counsels pursued those inquiries, but this time, the Justice Department, led by a Trump appointee, Attorney General William P. Barr, declined to investigate Trump’s conduct, leaving the fact-finding to Congress. After the disclosure of the whistleblower complaint, House Democrats quickly launched a probe, led by House Intelligence Committee Chairman Adam B. Schiff (D-Calif.), that has rapidly summoned key witnesses to private depositions, and now to public hearings.

While Republican lawmakers have participated at every stage of the probe, they have largely been cut out of decisions about how the investigation has been structured.

That, Cole said, has resulted in a situation in which Republicans of all stripes — ideologically, temperamentally and otherwise — have felt comfortable opposing the impeachment effort: “Even folks that had some questions about the president thought the process just was unfair.”

Among those is Rep. Mac Thornberry (R-Tex.), the ranking Republican on the House Armed Services Committee. The GOP veteran has shown clear discomfort with how Trump handled relations with Ukraine but has signaled he is disinclined to remove him from office.

“I believe it was inappropriate. I do not believe it was impeachable,” he said on NBC’s “Meet the Press” earlier this month.

Illustrating that not every anti-impeachment argument carries the presidential imprimatur, Trump tweeted his dismay just hours after the Nov. 10 interview: “There was NOTHING said that was in any way wrong. Republicans, don’t be led into the fools trap of saying it was not perfect, but is not impeachable. No, it is much stronger than that. NOTHING WAS DONE WRONG!”

But the wrong-but-not-impeachable argument could be Trump’s saving grace in the Senate, where a number of GOP lawmakers have signaled similar discomfort with how Trump conducted his Ukraine policy and could be disinclined to embrace more-sweeping, scorched-earth rebuttals.

“All you care about is, what are the votes on the board?” Cole said. “Anything that gets us to more no’s strengthens the president’s hand. If we come out of here with essentially a unanimous Republican no vote, how in the world is the Republican Senate going to turn their back on every member of the Republican caucus in the House?”

Multiple Republicans said this week that they simply did not expect the days of testimony to change any minds — whether on Capitol Hill or among Republican voters across the country.

Rep. Douglas A. Collins (R-Ga.), who as the top Republican on the House Judiciary Committee will play a lead role in the next phase of the impeachment process, said Republican lawmakers have simply become desensitized to Democratic attacks on Trump.

“There were voices saying the day after election, we should impeach him, so it’s been a constant drumbeat,” he said — echoing another frequent GOP talking point. “We believe that when you look at the sourcing of the facts, the facts don’t warrant impeachment. It’s easy for us to stand together on that. The bottom line is, there’s nothing impeachable. So our side is going to stick with president.”

JM Rieger contributed to this report.