Former Vice President Joe Biden announced his support for impeachment Wednesday, telling an audience in New Hampshire that President Donald Trump is making a mockery of the U.S. Constitution.

Biden officially tossed his support behind impeaching Trump, who has spent several weeks throttling the former vice president for his work in Ukraine while he served in the White House. The president is facing an impeachment inquiry after asking Ukraine’s president to investigate Biden.

“Donald Trump has violated his oath of office, betrayed this nation and committed impeachable acts. … He should be impeached,” Biden said . His comments are a sign the former Democratic frontrunner is ratcheting up his rhetoric targeting Trump.

Biden went on to shame the president. “Trump isn’t just testing us, he’s laughing at us. He has no sense of decency. … We have to prove him wrong. We have to prove that [we] are up to this moment, and this is an especially dangerous moment for this nation,” he said.

He was etching out a different message in September, when Biden called for impeachment only if Trump fails to comply with investigations. That likely changed after the White House sent a letter Tuesday to top House Democrats declaring that Trump will not comply with an inquiry.