Conservative commentators are questioning the loyalty of a Ukrainian-born National Security Council official set to speak to House investigators pursuing the impeachment inquiry into President Donald Trump.

The New York Times reported that the NSC's top expert on Ukraine, Lt. Col. Alexander Vindman, repeatedly raised concerns to his superiors and NSC lawyers that US policy towards Ukraine, including Trump's personal attorney Rudy Giuliani's efforts to pressure Ukraine to investigate Trump's political rival, was undermining US national security interests.

Vindman, who emigrated to the US from the former Soviet Union in the 1970s, is a decorated US Army officer, who earned a Purple Heart after being injured during a 2003 deployment to Iraq.

Former Bush administration lawyer John Yoo accused Vindman of spying for speaking to Ukrainian officials, saying, "I find that astounding and some people might call that espionage" on "Ingraham Angle" Monday night.

"I am a patriot, and it is my sacred duty and honor to advance and defend our country, irrespective of party or politics," Vindman said in his opening statement.

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Conservative commentators are questioning the loyalty of a Ukrainian-born National Security Council official and decorated Iraq War veteran set to speak to House investigators pursuing the impeachment inquiry into President Donald Trump.

On Monday night, The New York Times reported that the NSC's top expert on Ukraine, Lt. Col. Alexander Vindman, repeatedly raised concerns to his superiors and NSC lawyers that US policy towards Ukraine, including Trump's personal attorney Rudy Giuliani's efforts to pressure Ukraine to investigate Trump's political rival, was undermining US national security interests.

The impeachment inquiry an centers around a whistleblower complaint claiming Trump was "using the power of his office to solicit interference from a foreign country in the 2020 U.S. election" in a July 25 phone call with Ukrainian president Volodymyr Zelensky, which Vindman was on, just days after Trump ordered his administration to withhold a nearly $400 million military-aid package to Ukraine.

The White House's notes of the call show the US president brought up how the US does "a lot for Ukraine" and immediately after asked Zelensky to do him a "favor, though" by investigating former Vice President Joe Biden and a debunked conspiracy theory that Ukraine is in possession of a Democratic National Committee server.

"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," Col. Vindman said in the statement he plans to give to Congress, according to The Times. "I realized that if Ukraine pursued an investigation into the Bidens and Burisma it would likely be interpreted as a partisan play."

At the age of three, Vindman and his family fled the Soviet Union as refugees and moved to New York City, according to a New York Times profile of Vindman published Tuesday.

Vindman entered the US Army 1999 and completed multiple tours of duty in South Korea, Germany, and Iraq, where he was awarded a Purple Heart after being injured by an EID.

He is now an Army area foreign officer on the NSC specializing in the political implications of US military policy in Eastern Europe, and has previously served in US embassies in both Russia and Ukraine, The Times said.

But despite his two decades of military and national security service, Fox News hosts and guests, and a conservative CNN contributor have all suggested or outright claimed that Vindman's Ukrainian heritage puts his loyalty to the United States in doubt.

Fox News host Laura Ingraham quoted from a Times story reporting that Vindman advised Ukrainian officials on how to respond to Giuliani's overtures, and said, "here we have a U.S. National security official who's advising Ukraine while working inside the White House apparently against the president's interest."

Former Bush administration lawyer and conservative commentator John Yoo even went as far to accuse Vindman of possible spying for Ukraine, saying, "I find that astounding and some people might call that espionage, but it doesn't add any enough facts to what we know."

The next day on "Fox & Friends," co-host Brian Kilmeade said that Vindman "tends to feel simpatico with the Ukraine."

His co-host Ainsley Earnhardt further tried to downplay the substance of Vindman's concerns, saying, "Same transcript that you and I have read. Everyone has an opinion. Either you think the president did quid pro quo or you don't. Most of his base doesn't believe there was anything there. That's just how he does business."

Also on Tuesday morning, recently retired former Rep. Sean Duffy of Wisconsin, who is now a CNN contributor, questioned whether Vindman was "concerned about American policy" and claimed he had "an affinity" for Ukraine.

"This has been nagging at me the whole time here, because when I asked you about Col. Vindman, the very first thing you said was he was Ukrainian," CNN "New Day" co-host John Berman asked Duffy.

"So yes or no, do you trust Ambassador Bill Taylor more because he was born in the United States? Where does the location of his birth matter? Mark Meadows was born in France, is he pro-French by definition? That's a pretty stunning comment you made just there."

"So I read his statement, John, and I'm sure you did as well, and it seems very clear that he is incredibly concerned about Ukrainian defense. I don't know that he's concerned about American policy, but his main mission was to make sure that Ukraine got those weapons. I understand that. We all have an affinity to our homeland where we came from," Duffy replied.

"And so he's entitled to his opinion. He has an affinity for the Ukraine. He speaks Ukraine, and he came from the country and he wants to make sure they're safe and free. I understand that," Duffy added.

Both Berman and fellow CNN contributor Charlie Dent reacted in disbelief at Duffy's suggestion. Duffy eventually claimed he didn't know enough about Vindman to determine "whether he put America first."

"I don't know anything about him, so I can't judge whether he puts America first. I spent the last five years looking at Donald Trump fighting for the American people, and so I know he's trying to put them first. I can't judge him because I don't know him," Duffy added.

In a series of Tuesday morning tweets, Trump himself attacked Vindman, accusing him of being a "Never Trumper witness."

According to The Times, Vindman addresses his immigrant story in his statement to Congress, saying, "I sit here, as a lieutenant colonel in the United States Army, an immigrant. I have a deep appreciation for American values and ideals and the power of freedom. I am a patriot, and it is my sacred duty and honor to advance and defend our country, irrespective of party or politics."

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