An expert witness in Wednesday’s House Judiciary Committee impeachment hearing riffed on the name of the president’s teen son, Barron — drawing a swift and forceful rebuke from the Trump campaign.

“Contrary to what President Trump has said, Article 2 [of the Constitution] does not give him the power to do anything he wants,” testified Pamela Karlan, a professor at Stanford Law School. “The Constitution says there can be no titles of nobility, so while the president can name his son Barron, he can’t make him a baron.”

The wisecrack drew a strongly-worded clapback from Trump’s 2020 campaign.

“Only in the minds of crazed liberals is it funny to drag a 13-year-old child into the impeachment nonsense,” read a statement from campaign spokeswoman Kayleigh McEnany. “Pamela Karlan thought she was being clever and going for laughs, but she instead reinforced for all Americans that Democrats have no boundaries when it comes to their hatred of everything related to President Trump.”

The statement in turn invoked the son of former Vice President Joe Biden, whom Trump and other Republicans have repeatedly called on to testify in the impeachment hearings.

“Hunter Biden is supposedly off-limits according to liberals, but a 13-year-old boy is fair game,” McEnany continued. “Disgusting.”

The statement additionally called for Democrats to “immediately repudiate” Karlan, and demand an apology to the First Family.

Republican Florida Rep. Matt Gaetz, who sits on the committee, also jumped to the Trump family’s defense, scolding Karlan, “When you try to make a little joke out of referencing Barron Trump, that does not lend credibility to your argument.

“It makes you look mean and like you’re attacking someone’s family, the minor child of the President of the United States.”