(CNN) - Republicans are struggling to find a unified defense as they shift their ever-changing arguments about why President Donald Trump's actions are not impeachable, amid damaging testimony from senior diplomats that Trump sought to condition US military aid to Ukraine on opening investigations into his political rivals.
What once was a frequently repeated mantra -- there was no quid pro quo -- has now morphed into a multi-pronged and sometimes disjointed defense, with Republicans each taking the job into their own hands, hoping to fight back against the allegations raised daily with the release of new transcripts.
Republicans across the Capitol have resorted to attacking the firsthand knowledge of witnesses, muddying the waters with calls to name the whistleblower and even seeking to discredit the Trump administration's ability to be organized enough to execute a scheme to use military aid in order to advance its own political agenda.
"What I can tell you about the Trump policy toward Ukraine: It was incoherent, it depends on who you talk to, they seem to be incapable of forming a quid pro quo, so no I find the whole process to be a sham and I'm not going to legitimize it," Senate Judiciary Chairman Lindsey Graham, a South Carolina Republican, told reporters Wednesday.
The shifting strategy comes as a tidal wave of new information emerges from transcripts of key witnesses including US Ambassador to the European Union Gordon Sondland, who surprised lawmakers by amending his testimony and who made things more complicated for Republicans.
"That is Sondland's opinion," said Rep. Scott Perry, a Pennsylvania Republican, of Sondland's revised testimony. "These are all folks' opinions."
Sondland and the top US diplomat in Ukraine, Bill Taylor, both said they came to believe that any White House meeting with Ukraine's President or US military aid for Ukraine's government was tied to an announcement that the country would investigate Democratic presidential candidate Joe Biden.
"That was my clear understanding, security assistance money would not come until the President committed to pursue the investigation," Taylor told congressional investigators, according to the transcript.
New avenues of defense in the House
The transcripts have corroborated key points made in the whistleblower's initial complaint, but Republicans have also argued they've provided new avenues to poke holes in the Democrats' case.
Republicans seized on the fact that Taylor -- a career diplomat -- never talked directly to Trump about what the rationalization for withholding the aid. Republicans also touted testimony from former US Special Envoy to Ukraine Kurt Volker, who told investigators that he wasn't aware a quid pro quo existed.
"You asked what conversations did I have about a quid pro quo ... none because I didn't know there was a quid pro quo," Volker testified.
Republican Rep. Mark Meadows of North Carolina, a top ally of Trump's, touted Volker's testimony and said it was only getting "easier" to defend the President.
"It's actually getting easier," Meadows said.
Republicans have also argued that some witnesses have done little more than offer their opinions.
Republicans say that in Sondland's amended testimony where the ambassador said he recalled speaking with a top Zelensky aide and saying the "resumption of US aid would likely not occur until Ukraine provided the anti-corruption statement we had been discussing for many weeks" that it was just Sondland's opinion.
"He said he was making a presumption ... that's in his statement," the top Republican on the House Oversight Committee, Rep. Jim Jordan of Ohio, told reporters Wednesday.
But while Republicans are seizing on Volker's testimony to defend the President, there are signs that the former envoy wasn't aware of key conversations related to the US aid and investigations.
Volker testified that the Ukrainians were unaware that the aid was being held up until late August, when the push had already been dropped for them to open an investigation into Burisma and the 2016 election. But Sondland testified that he had told a top aide to Zelensky on September 1 that his understanding was in order for the military aid to be released, the Ukrainian had to announce investigations into Trump's political rivals, undercutting a key Republican talking point.
In the Senate
Across the Capitol, Senate Republicans' views are also evolving. While Vice President Mike Pence urged Republicans in a closed-door lunch Tuesday to lean on the transcript as evidence that there was no quid pro quo, some Republican senators have focused instead on arguing the President's actions have been problematic but are far from impeachable.
"The Senate will face the question of whether that's an impeachable offense. And I don't think the American people are going to conclude that it is," said Sen. Roger Wicker, a Republican from Mississippi.
Others have suggested it's not the Senate's role to defend Trump at every turn, as lawmakers will act in the role of jurors if the impeachment effort moves to a Senate trial.
"I think on the Senate side of the building, the best thing for us to do is to let the facts get assembled and try to figure out what they mean," said Sen. Roy Blunt, a Republican in leadership from Missouri.
Several Republicans have avoided answering questions about whether it's OK for Trump to ask Ukraine to probe his rivals.
One, Sen. Martha McSally of Arizona, took the long route -- around the Capitol and around parked cars -- to avoid cameras. Her aide stepped in front to say: "No comment."
Next week, Republicans will once again adapt to a changing landscape in the impeachment probe. They'll have to defend the President in public hearings after House Intelligence Chairman Adam Schiff announced Taylor, State Department official George Kent and former US Ambassador Marie Yovanovitch will testify.
"Those open hearings will be an opportunity for the American people to evaluate the witnesses for themselves and make their own determinations about the credibility," the California Democrat said Wednesday.
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