President Joe Biden’s nominee for the No. 3 civilian at the Pentagon faced a contentious confirmation hearing Thursday with Republican senators taking aim at his fiery tweets in the last four years that they considered “incendiary,” “intemperate and imbalanced insults.”

Sen. Tom Cotton was the first at the Armed Services Committee hearing to center on some of the specifics of Colin Kahl’s online presence during President Donald Trump’s administration. The Arkansas Republican took issue with a tweet from October 2019 in which the former Pentagon staffer and Biden aide criticized GOP support for Trump’s decision to unilaterally and suddenly withdraw forces from Syria, clearing the way for a Turkish assault on local forces that had fought and died for American interests there.

“The GOP used to pride itself as a party that put values front and center in US foreign policy. Now—as they debase themselves at the alter of Trump—they are the party of ethnic cleansing,” Kahl wrote at the time.

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Cotton said such “volatile outbursts” demonstrate a lack of good judgement and would poison Kahl’s relationship with Congress as well as with his colleagues at the Pentagon were he approved to become the undersecretary for policy. Cotton said he – like many others who would speak on Thursday – will oppose Kahl’s nomination.

Sen. Joni Ernst of Iowa similarly said she won’t support Kahl over a post in which he criticized Trump’s decision to fire then-national security adviser H.R. McMaster and replace him with John Bolton, saying at the time that the decision meant, “We are going to die.”

“This demonstrates that these exaggerated views and incendiary remarks are not what we are looking for in someone who will serve in advising policy within the DOD,” Ernst said.

Sen. Marsha Blackburn of Tennessee later added, “This is a concern to many of us on the committee because your language really is not representative of the way a top political official at the Pentagon should write about policy.”

Some Democrats on the committee were quick to point out what they considered the hypocrisy of blaming Kahl for his posts without referencing the vitriol that often came from then-President Donald Trump’s online presence – conduct that resulted in Twitter permanently banning him from the platform in January.

Not mentioning Trump’s “lying, racist tweets,” Sen. Mazie Hirono of Hawaii said, “is pretty rich.”

Kahl in response to Cotton apologized for what he considered “disrespectful” language.

“I understand that the position of the undersecretary of defense for policy, while it’s a political appointment, is not a political job. It’s a policy job,” Kahl said. “One that requires me to be nonpartisan.”

“I know I can comport myself that way because I did it the last time I was at the Pentagon,” said Kahl. In addition to serving as then-Vice President Biden’s national security adviser, Kahl also served as deputy assistant secretary of defense for Middle East affairs among other positions at the Pentagon and in academia.

In addition to criticism about his social media presence, Republicans on the dais also slammed Kahl’s role in negotiating the 2015 Iran nuclear deal but struggled to find specific points of disagreement regarding the need to continue to contain Iran’s malign activity in the Middle East.

They also claimed Kahl lacked adequate judgement to hold a top position at the Pentagon because he believed previous decisions by the Trump administration would lead to war, including moving the U.S. Embassy in Israel to Jerusalem and killing Iranian Gen. Qassem Soleimani in a drone strike.