Army Lt. Col. Alexander Vindman, director of European Affairs on the National Security Council, reportedly told Ukrainian President Volodymyr Zelensky not to get entangled in U.S. domestic politics after Ukraine officials asked him about how to handle Rudy Giuliani, according to the Wall Street Journal.

The newspaper reported:

[Vindman] told House investigators that Ukrainian government officials had repeatedly asked him about the role of Mr. Trump’s personal attorney, Rudy Giuliani, and whether he speaks for the U.S. government. Mr. Giuliani had been “making demands,” this person said, in summarizing Col. Vindman’s testimony, and the Ukrainian government wanted to know how to handle him. Col. Alexander Vindman responded by telling the government in Kyiv that Mr. Giuliani doesn’t speak for the National Security Council and that he was only authorized by his boss, then-national security adviser John Bolton to discuss policy directives. Col. Vindman offered Mr. Zelensky some personal advice while attending his May 2019 inauguration not to get entangled in U.S. domestic politics, the person familiar with Col. Vindman’s testimony said.

Giuliani, who defended Trump during the FBI’s probe into alleged Russia collusion by the Trump campaign, has been investigating the origins of those allegations, as well as Joe Biden and his son Hunter Biden, who sat on the board of a Ukrainian company earning $50,000 a month while his father was vice president.

Vindman testified earlier this week to Congress as part of House Democrats’ impeachment probe.

According to his opening statement that was leaked to press, Vindman said he was concerned by Trump’s request to Ukraine that they help investigate the origins of the FBI’s investigation and Biden.

Vindman said he was afraid that it would lead to Ukraine losing bipartisan support in the U.S. and he said he reported the call to the NSC’s lead counsel:

I was concerned by the call. I did not think it was proper to demand that a foreign government investigate a U.S. citizen, and I was worried about the implications for the U.S. government’s support of Ukraine. I realized that if Ukraine pursued an investigation into the Bidens and Burisma, it would likely be interpreted as a partisan play which would undoubtedly result in Ukraine losing the bipartisan support it has thus far maintained. This would all undermine U.S. national security. Following the call, I again reported my concerns to NSC’s lead counsel.

He also said in his testimony:

The United States and Ukraine are and must remain strategic partners, working together to realize the shared vision of a stable, prosperous, and democratic Ukraine that is integrated into the Euro-Atlantic community. Our partnership is rooted in the idea that free citizens should be able to exercise their democratic rights, choose their own destiny, and live in peace.

The WSJ also reported that Vindman’s brother, who is also a lieutenant colonel in the Army and also works at the NSC but as an ethics lawyer, may be called to testify as part of the impeachment inquiry.

Vindman reportedly testified that his brother, Army Lt. Col. Yevgeny Vindman, had witnessed the decision to move Trump’s July 25 phone call transcript to a top secret server.

Vindman reportedly asked his brother to accompany him in his capacity as an NSC ethics lawyer when he reported the phone call to the NSC’s general counsel, John Eisenberg.

Eisenberg and his deputy, Michael Ellis, reportedly then began discussing what to do with the transcript, given its “sensitive nature,” and then suggested storing it on a top secret server.

Vindman, who listened to the call, reportedly testified that he made some “minor revisions” to the transcript but that they were not included in the final version.

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