A bipartisan group of lawmakers echoed then-Vice President Joe Biden’s push for anti-corruption reforms in Ukraine, including within the country’s office of the prosecutor general, according to a 2016 letter unearthed by CNN. In the letter, Sens. Rob Portman (R-Ohio) and Dick Durbin (D-Ill.), co-chairs of the bipartisan Senate Ukraine Caucus, pressed Ukraine’s then-President Petro Poroshenko to take action on “entrenched corruption” within his government. “We recognize ‎that your governing coalition faces not only endemic corruption left from decades of mismanagement and cronyism, but also an illegal armed seizure of territory by Russia and its proxies,” they wrote in the letter. ”[We] urge you to press ahead with urgent reforms to the Prosecutor General’s office and judiciary.” The letter ― also signed by Sens. Ron Johnson (R-Wis.), Mark Kirk (R-Ill.), Chris Murphy (D-Conn.), Jeanne Shaheen (D-N.H.), Richard Blumenthal (D-Conn.) and Sherrod Brown (D-Ohio) ― appears to undermine President Donald Trump’s unsubstantiated claim that there was “quid pro quo” when then-Vice President Biden withheld aid to Ukraine to push the country’s leaders to fire its prosecutor general, Viktor Shokin. Trump claims Biden did so for the purpose of impeding an investigation into Burisma, a Ukrainian gas company upon whose board Hunter Biden served. No evidence has been brought to light to suggest this.

NBC NewsWire via Getty Images Sens. Dick Durbin (D-Ill.), left, and Rob Portman (R-Ohio), right, appear on "Meet the Press" in 2013.

Biden boasted in 2018 about withholding $1 billion in aid to Ukraine to get them to oust Shokin, which Trump has claimed amounts to a “quid pro quo.” But foreign policy experts, including a former U.S. ambassador to Ukraine, say Biden’s actions were an appropriate form of diplomatic pressure. Biden wasn’t the only person calling for Shokin’s removal from office. Members of Congress (as evidenced by the 2016 letter of support), European leaders and international organizations were all pushing for the notoriously corrupt prosecutor to be fired. Shokin’s office had opened an investigation into Burisma, but it was dormant by the time Biden was working on anti-corruption efforts in Ukraine. Ukrainian authorities have cleared Biden of any wrongdoing related to Shokin’s firing. Neither Portman nor Kirk, who is no longer in office, immediately responded to HuffPost’s requests for comment. Johnson wrote a letter with Sen. Chuck Grassley (R-Iowa) last week that, in part, called on Attorney General William Barr to investigate allegations that Biden called for Shokin’s removal to help his son. “The United States, the European Union, the I.M.F., and Ukraine’s leading reform figures were all pressing for Viktor Shokin to be removed from office because he was one of the biggest obstacles to fighting corruption in the entire country,” Biden campaign spokesman Andrew Bates told HuffPost in a statement. “This was a bipartisan goal in Congress as well,” he added. “It is unfortunate that Senator Johnson seems to have forgotten a time when he put the country’s values over his own politics, but perhaps re-reading his well-articulated words whole-heartedly agreeing with Joe Biden’s push to move the anti-corruption cause in Ukraine forward will help him on his journey back to intellectual consistency.” Asked for comment, a spokesperson for Johnson referred HuffPost to comments the senator made Wednesday during an interview with radio station WRRD. “I don’t know what’s true, I don’t know what’s not true,” Johnson said while discussing some of the issues referenced in the letter he wrote with Grassley. “If something happened, the American people should know. If something didn’t happen, the American people need to know so we can get this behind us. It’s about uncovering the truth.”

ASSOCIATED PRESS Then-Vice President Joe Biden, left, waves as he walks out of Air Force Two with his granddaughter Finnegan Biden and son Hunter Biden in 2012.