WASHINGTON Republicans now maintain President Donald Trump was completely justified in engaging in a quid pro quo with Ukraine after an extended period of time adamantly denying that it had ever happened at all.

Last year, after the White House released a summary of Trumps infamous July 25 conversation with Ukrainian President Volodymyr Zelensky, Republicans insisted that they saw no evidence of a direct link between security assistance to Ukraine and the opening of investigations into former Vice President Joe Biden , a potential Trump opponent in the 2020 election.

It clearly isnt a quid pro quo, Sen. Kevin Cramer (R-N.D.) said in November after several top U.S. diplomats testified before the House that the Trump administration did, in fact, withhold aid to Ukraine in exchange for an investigation into a political opponent.

Read the call record, they said over and over again, and its clear that the aid and the investigations werent linked.

If you could show me that Trump actually was engaging in a quid pro quo, outside the phone call, that would be very disturbing, Sen. Lindsey Graham (R-S.C.) told Axios in October .

Their position echoed White House talking points sent to Republicans on Capitol Hill (and mistakenly also to some Democrats ) following Trumps repeated denials on Twitter that there was no quid pro quo.

Lets be clear, there was no quid pro quo for Ukraine to get US aid in exchange for looking into Biden or his son, said one of the talking points .

But Republicans changed their story on the matter this week after The New York Times revealed the existence of a book manuscript from former national security adviser John Bolton. The book, which is due to be released later this year, alleges that Trump told Bolton directly that the aid to Ukraine was tied to the Ukrainian government opening investigations into Biden and his son.

The revelation from a first-hand witness threatened to derail Republican desires for a quick acquittal of Trump in the Senate impeachment trial this week and upped the pressure on them to allow witnesses such as Bolton to testify and new documents to be presented during the proceedings.

During their opening arguments in the Senate, Trumps defense team contended that even if Boltons account were true, it would not merit the removal of a president during an election year. Their argument opened the door for some Republican senators to acknowledge that Trump did, in fact, withhold Ukraine aid, but that it didnt merit his removal from office because he was morally justified in seeking investigations into the Bidens.

It is clear to me that there is ample evidence for the President to be concerned about conflicts of interest on behalf of Hunter Biden and that Vice President Joe Bidens failure to take appropriate action was unacceptable. This combination, in my view, undercut Americas message on reforming corruption in Ukraine, Graham said in a statement on Wednesday.

Theres no evidence that Biden or his son Hunter engaged in corruption in Ukraine. Kurt Volker, the former U.S. special envoy for Ukraine, also testified in the House inquiry that he saw no validity to Trumps allegations against the Bidens.

Trump and other Republicans only began inquiring about Hunter Bidens role on the board of an energy company in Ukraine after his father announced his campaign for president.

Other Republican senators were equally dismissive of Boltons allegations, maintaining this week that Trump had an official reason to insist on an investigation into the Bidens, rather than a personal one.

Quid pro quo doesnt matter, Sen. Ted Cruz (R-Texas) said during an interview with Fox News Sean Hannity on Tuesday.

[Boltons] point is what? That doesnt tell us anything, Sen. John Kennedy (R-La.) added in a separate Tuesday interview with Hannity.

Asked about Boltons books account on Wednesday, Sen. Richard Shelby (R-Ala.) said, I dont think there was any crime. I dont think it was an impeachable offense.