Democratic presidential candidate Joe Biden said Wednesday for the first time that President Donald Trump must be impeached for abusing the powers of his office to help his own reelection.

Biden said Trump is “shooting holes in the Constitution” by asking foreign powers to interfere in the 2020 election and then refusing to cooperate with a resulting House impeachment inquiry.

Trump quickly shot back in a tweet that it was “so pathetic” to see Biden calling for his impeachment. The president maintained that he had done nothing wrong.

“This is a president who has decided this nation doesn’t have the tools, the power, the political will” to punish bad behavior, Biden said. “He’s not just testing us. He’s laughing at us.”

Trump in a July phone call to Ukraine’s leader had asked for “a favor” of investigating Biden and his son Hunter. House Democrats have begun impeachment proceedings against Trump based on a rough transcript of the July 25 telephone call.