The lone Democrat in Kentucky’s Congressional delegation has announced he will not attend Donald Trump’s inauguration festivities, joining a growing number of elected officials boycotting the event.

Rep. John Yarmuth, who represents Kentucky’s 3rd Congressional district, said he declined the invitation because Trump has not acted in a presidential manner and has damaged the prestige of the office.

“From insulting and accusing the director of the CIA to getting up in the middle of the night and tweeting about Saturday Night Live to insulting an American hero like John Lewis, and attacking so many of the people and the categories of the people he is supposed to be leading, he has not acted in my opinion like a serious adult,” Yarmuth said during an interview on Tuesday.

Trump has been locked in a war of words with Georgia Democratic Rep. John Lewis, a civil rights icon who questioned the legitimacy of Trump’s election in the wake of revelations that Russian-sponsored hacking may have played a role in Trump’s win over Hillary Clinton.

In a statement released Monday, Yarmuth said he wasn’t questioning the legitimacy of Trump’s election.

“As the transition of power is a hallmark that must be honored, this is not a decision I make lightly,” Yarmuth said. “It’s not my intent to protest the election results or to make a statement about policy.”

Yarmuth was re-elected to his 6th term in Congress representing the Democrat-heavy district that surrounds Louisville.

Republican Rep. Thomas Massie, who represents the 4th Congressional district in Northern and Eastern Kentucky, took to Twitter to criticize Democrats planning to sit out of the ceremonies.

“Disappointed when Obama won his second term, but I attended his inauguration,” Massie wrote. “Also attended all SOTU speeches. Now it’s ur turn D’s.”

More than 30 members of Congress say they plan to boycott Trump’s inauguration.

Ryland Barton is the Managing Editor for Collaboratives.