Kurt Volker, the former U.S. special representative to Ukraine, defended former vice president Joe Biden in a statement to Congress on Thursday and said he was trying to run interference on information being supplied to President Trump by former New York mayor Rudolph W. Giuliani, to secure continued U.S. support for the government in Ukraine.

Volker, who as of Thursday was the executive director of the McCain Institute for International Leadership, said he did not believe allegations Giuliani has leveled against Biden, namely that Biden was influenced in his dealings with the Ukrainian leadership by his son’s presence on the board of a Ukrainian gas company whose owner was being probed by authorities in Kiev. (Cindy McCain, a Biden friend, chairs the McCain Institute.)

“I have known former vice president Biden for 24 years, and the suggestion that he would be influenced in his duties as vice president by money for his son simply has no credibility to me,” Volker said, according to a written copy of the opening statement reviewed by The Washington Post. “I know him as a man of integrity and dedication to our country.”

Biden is seeking the 2020 Democratic presidential nomination.

Volker sought to present himself in the testimony as a man caught in the middle of Giuliani’s efforts to pressure the Ukrainian leadership for Trump’s domestic political purposes and Ukrainian President Volodymyr Zelensky’s attempts to maintain U.S. support for Ukraine and win a meeting with Trump.

Volker said he told Giuliani that the information he was receiving from former Ukrainian prosecutor general Yuri Lutsenko was not credible. “I believed that these accusations by Mr. Lutsenko were themselves self-serving, intended to make him appear valuable to the United States, so that the United States might weigh in against his being removed from office by the new government,” Volker said. 

He said his efforts to persuade Trump to support Zelensky were undermined by information that Giuliani and others had been feeding the president. Among other things, Volker suggested that Trump had bought into a theory — widely pushed by former Trump campaign chairman Paul Manafort’s team — that the Ukrainians conspired with Democrats during the 2016 election to undermine Trump and support Hillary Clinton. 

“The president was very skeptical,” Volker said, recalling a May 23 meeting with Trump at the White House. “He said that Ukraine was a corrupt country, full of ‘terrible people.’ He said they ‘tried to take me down.’ In the course of that conversation, he referenced conversations with Mayor Giuliani. It was clear to me that despite the positive news and recommendations being conveyed by the official delegation about the new president, President Trump had a deeply rooted negative view on Ukraine rooted in the past.”

Volker said he was trying to ensure the Trump administration continued its support for Ukraine. “In carrying out this role, I at some stage found myself faced with a choice: to be aware of a problem and to ignore it, or rather to accept that it was my responsibility to try to fix it,” Volker said. “I would not have been true to myself, my duties, or my commitment to the people of the United States or Ukraine, if I did not dive in and try to fix problems as best I could.”

Volker, who was serving in the special-envoy position in an unpaid capacity, said he was not on the July 25 call in which Trump pressed Zelensky to investigate Biden and his family. He said he received only a general readout of the conversation.

Volker was also working as executive director of the McCain Institute and was a consultant for the lobbying firm BGR, which counted the defense contractor Raytheon and the Ukrainian government as clients until last year. Raytheon is part of a joint venture that manufactures Javelin antitank missiles, which the Trump administration agreed to supply to Ukraine. BGR said Volker recused himself from Ukraine government work at the firm when he started the special-envoy job. 

Volker’s statement casts the president’s reluctance to meet with Zelensky as having little to do with Biden or Burisma but instead related to his “long-held negative view towards Ukraine” and Giuliani’s assertion of Ukrainian malfeasance in the 2016 election. He cast himself as innocently working to improve the bilateral relationship and suggested that Trump’s bigger focus was on persuading the Ukrainians to investigate the 2016 election with a view to undermining the case that the Russians had interfered on his behalf. 

In a text message ahead of the July 25 phone call, Volker told an adviser to Zelensky: “Heard from White House — assuming President Z convinces trump he will investigate / ‘get to the bottom of what happened’ in 2016, we will nail down date for visit to Washington. Good luck! See you tomorrow — kurt.” 

However, it is clear from the text messages Volker knew by Aug. 10 that a renewed investigation of Burisma, the gas company where Hunter Biden served on the board, along with a probe of Ukraine and the Democrats during the 2016 election, were viewed in Kiev as a quid pro quo for the Ukrainian president to secure a date for a White House summit with Trump. 

“Once we have a date, will call for a press briefing, announcing upcoming visit and outlining vision for the reboot of US-UKRAINE relationship, including among other things Burisma and election meddling investigations,” Andrey Yermak, an aide to Zelensky, wrote in an Aug. 10 message to Volker.

“Sounds great!” Volker responded.

Volker and the U.S. ambassador to the European Union, Gordon Sondland, worked on a draft statement for the Ukrainians so they could satisfy Trump’s demands. After sending it to Giuliani, who wanted an explicit reference to Burisma and the 2016 election investigation, the two messaged back and forth to work up the text to send back to the Ukrainians, according to Volker. The Ukrainians ultimately did not agree to the statement upon receiving that version. 

Volker said that Zelensky’s aide replied by saying that the Ukrainian government did not want to mention Burisma and the 2016 election directly. Volker said he agreed with their decision and said he reiterated it was essential Ukraine do nothing that could be seen as interfering in the 2020 election. Zelensky’s aide agreed, Volker said, “and the idea of putting out a statement was shelved.”

Suggesting language to send back to the Ukrainians in a later August text, Volker wrote to Sondland: “We intend to initiate and complete a transparent and unbiased investigation of all available facts and episodes, including those involving Burisma and the 2016 U.S. elections, which in turn will prevent the recurrence of this problem in the future.” 

“Perfect. Let’s send to Andrey after our call,” Sondland replied, referring to Yermak by his first name.

Volker also pleaded ignorance of Trump’s July 25 call in which he raised investigating Burisma and Biden with Zelensky, saying he received a general readout of the conversation from people who described it as a “good, congratulatory call.” He said he learned the full details about the call only when it was released late last month.