President Donald Trump may not have ultimately been successful in his pressure campaign to get the Ukrainian government to investigate former Vice President Joe Biden—but at least he has Senator Lindsey Graham to do his bidding instead. Graham, who chairs the Senate Judiciary Committee, signaled his intention Thursday to investigate Joe and son Hunter Biden's dealings in Ukraine, legitimizing an unsubstantiated right-wing conspiracy theory that has gained notoriety through the current impeachment proceedings. The senator sent a letter to Secretary of State Mike Pompeo requesting documents related to Biden and Burisma, the Ukranian energy company on whose board Hunter Biden previously served, in order to investigate the theory that the then-V.P. improperly ordered the firing of former Ukrainian Prosecutor General Viktor Shokin in order to end Shokin's investigation into Burisma.

Graham suggested Thursday in his letter that he'll be focusing on Joe Biden's conversations with former Ukrainian President Petro Poroshenko, as well as a 2016 meeting between Devon Archer, a business partner of Hunter Biden's, and then-Secretary of State John Kerry. (A former Kerry aide told the Washington Post the meeting was a “courtesy hello to a 2004 alumni” of Kerry’s presidential campaign and was “100 percent unrelated to Burisma.”) Graham had previously told the Post in late October that he would not give into GOP pressure and “turn the Senate into a circus” by investigating the Bidens. But the escalating impeachment inquiry—which has gotten worse and worse for the Trump administration with each testifying witness—seems to have changed the loyal Trump ally's mind. Graham spokeswoman Taylor Reidy told the Post that the senator was now asking for the documents because “Adam Schiff and the House Intel Committee have made it clear they will not look into the issues about Hunter Biden and Burisma.” “Graham is requesting documents which could shed additional light on that issue and hopes they will be able to answer some of the outstanding questions,” Reidy added.

House Republicans have seized on the Biden conspiracy theory—along with a similarly false conspiracy regarding the 2016 election—in the House Intelligence Committee's recent impeachment hearings, pushing the baseless theory on the committee's witnesses and making it a centerpiece of their impeachment defense. Like the GOP's numerous other flimsy impeachment defenses, however, this strategy has not fared well. The respected career foreign service officials who have testified before the committee have been quick to shoot down the right-wing theory, with officials including Lt. Col. Alexander Vindman, Jennifer Williams, and George Kent all testifying under oath that they had no evidence to support the idea that Biden had behaved improperly. (Graham may not realize this, as he publicly refused to watch the impeachment hearings, or even read the transcripts from previous closed-door testimony.) Kent, the State Department's top Ukraine official, said in his opening statement that although he “raised my concern that Hunter Biden’s status as a board member could create the perception of a conflict of interest,” he “did not witness any effort by any U.S. official to shield Burisma from scrutiny.” “In fact, I and other U.S. officials consistently advocated re-instituting a scuttled investigation of Zlochevsky, Burisma’s founder, as well as holding the corrupt prosecutors who closed the case to account,” Kent testified.

Kent and former Ambassador to Ukraine Marie Yovanovitch testified that the former vice president was acting in accordance with official U.S. policy when he pressured the Ukrainian government to terminate Shokin, with Yovanovitch noting the move “was endorsed and was the policy of a number of other international stakeholders, other countries, other monetary institutions, financial institutions.” Ukranian embassy official David Holmes testified Thursday that the Biden conspiracy was instead a product of Shokin's replacement, former Prosecutor General Yuriy Lutsenko, who retaliated against Yovanovitch over her “refusal to support him until he followed through with his reform commitments and ceased using his position for personal gain.” Lutsenko launched a smear campaign against Yovanovitch that would ultimately lead to her ouster—and as part of that, Holmes testified, made the “unsupported [allegation] ... that the embassy had allegedly pressured Lutsenko's predecessor to close a case against a different former Ukrainian official solely because of alleged connection between that official's company Burisma and former Vice President Biden's son.” (Lutsenko would soon become Rudy Giuliani's key Ukrainian contact, after being introduced to the Trump attorney by now-indicted businessmen Lev Parnas and Igor Fruman.)