Oct. 4 (UPI) -- House Democrats subpoenaed the White House and Vice President Mike Pence on Friday for documents related to their impeachment inquiry into President Donald Trump's dealings with Ukraine.
The chairmen of three committees investigating the Trump administration requested documents tied to Trump's July 25 phone call with Ukrainian President Volodymyr Zelensky in which the U.S. president pressed Ukraine to investigate former Vice President Joe Biden. The committees -- oversight and reform, intelligence, and foreign affairs -- have sent multiple subpoenas and deposition requests since House Speaker Nancy Pelosi of California announced a formal impeachment inquiry Sept. 25.
"We deeply regret that President Trump has put us -- and the nation -- in this position, but his actions have left us with no choice but to issue this subpoena," Reps. Elijah Cummings, D-Md., Eliot Engel, D-N.Y., and Adam Schiff, D-Calif., said in a letter to chief of staff Mick Mulvaney.
The chairmen sent a separate letter to Pence requesting documents that could determine what, if anything, the vice president knew of Trump's pressure on Ukraine to investigate the Bidens.
"Recently, public reports have raised questions about any role you may have played in conveying or reinforcing the President's stark message to the Ukrainian President," the letter read.
"The reports include specific references to a member of your staff who may have participated directly in the July 25, 2019, call, documents you may have obtained or reviewed, including the record of the call, and your September 1, 2019, meeting with the Ukrainian President in Warsaw, during which you reportedly discussed the Administration's hold on U.S. security assistance to Ukraine."
Earlier Friday, intelligence community Inspector General Michael Atkinson testified before the panel behind closed doors as part of an investigation spurred by a whistle-blower complaint over the July 25 phone call.
Atkinson's appearance followed lengthy private testimony from former U.S. Ambassador to Ukraine Kurt Volker before the committee on Thursday -- and later the release of text message exchanges among Trump administration officials discussing dealings with Ukraine. Twenty-five pages of text messages were released by the Democratic chairmen of three House committees.
Democratic lawmakers say the messages help clarify whether Trump threatened to withhold tens of millions of dollars in military aid to Ukraine unless Kiev agreed to investigate 2020 Democratic presidential candidate Joe Biden and his son, Hunter Biden.
The messages involve Volker, Giuliani, Ukrainian official Andriy Yermak and others.
Excerpts of the text messages were sent to Cummings, Engle and Schiff along with a letter saying the messages make clear why Pompeo has discouraged former Trump officials from providing testimony.
"These text messages reflect serious concerns raised by a State Department official about the detrimental effects of withholding critical military assistance from Ukraine, and the importance of setting up a meeting between President Trump and the Ukrainian president without further delay," the letter states.
The lawmakers said the excerpts are "only a subset of the full body of the materials," which they eventually plan to release.
In one text message, a senior American diplomat expressed outrage that the administration would withhold military aid until Ukraine complied with demands from Trump and Giuliani. The messages also revealed that top diplomat William Taylor threatened to resign last month amid concerns that Trump was withholding Ukrainian aid. Taylor has been the charge d'affaires at the U.S. Embassy in Kiev since June.
Taylor expressed concern that Trump would renege on the delivery of $400 million in military aid and strain relations between Washington and Kiev, to the benefit of Russia, which has occupied several border territories and the Crimea Peninsula since before fighting began in eastern Ukraine in 2014.
"The nightmare is they give the interview and don't get the security assistance," Taylor said in a message to Volker and Gordon Sondland, the U.S. ambassador to the European Union. "The Russians love it. (And I quit)."
"The message to the Ukrainians (and Russians) we sent with the decision on security assistance is key," he added. "With the hold, we have already shaken their faith in us. This is my nightmare scenario.
"It's crazy to withhold security assistance for help with a political campaign."
Sondland, however, argued that wasn't Trump's intention, and said, "We have identified the best pathway forward.
"I believe you are incorrect about President Trump's intentions," Sondland wrote in a message to Taylor. "The president has been crystal clear: no quid pro quo of any kind. The president is trying to evaluate whether Ukraine is truly going to adopt the transparency and reforms that President Zelensky promised during the campaign."
The upshot of Volker's testimony Thursday differed among Republicans and Democrats.
But some Republican lawmakers on the panel argued Volker's testimony cleared Trump of wrongdoing and furnished new evidence against Hunter Biden, who worked for five years on the board of a Ukrainian gas company.
"The allegations of a quid pro quo, basically today just blew a massive hole throughout the entirety of that argument," Rep. Lee Zeldin, R-N.Y., said Thursday. "The administration is in an even stronger place today than they were this morning as a product of Ambassador Volker coming to testify."
Speaking to reporters before he departed the White House for Florida on Thursday, Trump reiterated that Ukraine should investigate the Bidens and also urged the Chinese government to do the same. Hunter Biden was involved in an investment fund that had raised money in China.
More depositions are scheduled for next week, including testimony from Marie Yovanovitch, Trump's former ambassador to Ukraine. She was originally scheduled to testify Wednesday, but her appearance was delayed after Pompeo said she needed more time to prepare. She will now appear Oct. 11.