Former U.S. Rep. Sean Duffy is having a rough time with his analyst gig on CNN.

In fact, #FireSeanDuffy was trending on Twitter Tuesday after Duffy was harshly criticized in the wake of appearing to challenge the allegiance of Lt. Col. Alexander Vindman.

Vindman's family fled Ukraine when he was 3. He is a National Security Council Ukraine expert and in prepared testimony to the U.S. House impeachment inquiry said he raised concerns with officials about President Donald Trump's phone call with the Ukraine president.

During a Tuesday morning interview on CNN, Duffy said of Vindman, "it seems very clear that he is incredibly concerned about Ukrainian defense. I don't know if he's concerned about American policy. But his main mission was to make sure that the Ukraine got those weapons."

Later, Duffy sought to defend his remarks in a tweet, calling Vindman "an American war hero."

Mark Hertling, a retired U.S. Army General who served in Iraq, excoriated Duffy, calling the on-air comments "disgusting."

Without naming Duffy, the liberal group VoteVets.org accused allies of the president with "smearing" Vindman.

CNN's Brianna Keilar also took off on Duffy, and said: "That's some anti-immigrant bigotry and it’s an odd questioning of patriotism." She contrasted Duffy spending part of his 20's on reality TV, while Vindman served in Iraq.

A former reality TV personality, Susie Meister, even took a jab at Duffy, who appeared on the MTV show "Real World."