Former Vice President Joe Biden has joined the deluge of Democrats calling for the initiation of impeachment proceedings against President Donald Trump if he refuses to comply with congressional investigations into his administration.

“Using its full constitutional authority, Congress, in my view, should demand the information it has a legal right to receive,” Biden said on Tuesday afternoon, speaking from his hometown of Wilmington, Delaware.

If Trump refuses to cooperate, he continued, “Donald Trump will leave Congress, in my view, with no choice but impeachment. That would be a tragedy, but a tragedy of his own making.”

“I can take the political attacks,” Biden said, “but if we allow a president to get away with shredding the U.S. Constitution, that will last forever.”

Biden’s call for Trump’s impeachment makes him the highest-profile Democrat to join the swell of elected officials and presidential candidates—including centrists and so-called “frontline” Democrats, who hold seats in districts Trump won in 2016—supporting an impeachment investigation into the president.

The groundswell comes days after the Washington Post first reported that Trump was the subject of a whistleblower complaint filed with the intelligence community’s inspector general, which allegedly addresses multiple attempts by Trump to pressure the Ukrainian government into investigating Biden himself. The complaint has not yet been turned over to Congress, despite provisions of the Intelligence Community Whistleblower Protection Act requiring the director of national intelligence to forward such complaints to the Senate and House intelligence committees.

Hunter Biden, the former vice president’s son, is a former adviser and member of the board of director for Burisma, a Ukrainian energy company that has been the subject of corruption investigations by that country’s government. Biden, as vice president, pressured the Ukrainian government on behalf of the United States to fire the investigator who was accused of blocking international corruption investigations, including probes of Burisma, and had pushed its government to pull back on its reliance on Russian natural gas.

Trump has since accused Biden, without offering evidence, of pressuring Ukraine into firing the investigator in order to protect his son. He admitted on Monday he asked the Ukrainian government to investigate his top-polling political rival, even as he denied it was wrong to do so.

“You’re going to see because what we are doing is we want honesty and I think with the new president you’re going to see much more honesty in the Ukraine and that’s what we’re looking for,” Trump told reporters in New York City, ahead of the United Nations General Assembly. “We want to make sure that country is honest. It’s very important to talk about corruption. If you don’t talk about corruption, why would you give money to a country that you think is corrupt?”

Minutes before Biden’s address, Trump announced on Twitter that he was authorizing “the complete, fully declassified and unredacted transcript” of his July 25 call with Ukrainian President Volodymyr Zelensky. It was during this call that Trump is alleged to have pressured Zelensky up to eight times to investigate Biden’s connection with Burisma.

In another tweet, Trump characterized the call as “a very friendly and totally appropriate call,” with no explicit requests that Zelensky investigate the Bidens in exchange for military aid. On Monday evening, the Post reported that Trump had ordered acting chief of staff Mick Mulvaney to withhold $400 million in congressionally appropriated military aid to Ukraine ahead of his call with Zelensky.

Biden, who has accused Trump of an “overwhelming abuse of power,” had nonetheless been one of the last holdouts among his party’s presidential candidates on the issue of impeachment. In October 2018, Biden cautioned fellow Democrats against impeachment, and held off supporting impeachment proceedings against the president as late as Sunday.

“He could be impeached, but I’m not making that judgment now,” Biden told reporters over the weekend. “The House should investigate this. This appears to be an overwhelming abuse of power to get on the phone with a foreign leader who is looking for help from the United States and ask about me and imply things if that's what happened.”

Earlier in the day, Sen. Bernie Sanders (I-VT) issued a stronger statement on impeachment than he had previously, saying that he “hopes very much that Judiciary Committee will move forward with an impeachment inquiry.”

“Today, I call upon the Judiciary Committee to demand all of the information that they need from the Trump administration,” Sanders said in Davenport, Iowa. “Enough is enough,” he said, adding that Congress needs to demonstrate that they can “walk and chew bubble gum at the same time.”

In June, Sanders said that the committee should begin an inquiry, but he has previously also expressed concern that sole focus on impeachment could take away from messaging Democrats could do on issues of health care, climate change, and wages.

As frontrunners for the Democratic presidential nomination and, in Biden’s case, the target of the alleged corruption at the center of the scandal, Biden’s and Sanders’ calls add new urgency to the question of a formal impeachment investigation by the House of Representatives.

House Speaker Nancy Pelosi has been reluctant to cosign impeachment efforts—telling reporters that Trump is “just not worth it.” But as statements in support of the effort cascaded from nearly every corner of the Democratic Party, she announced on Tuesday morning that she would consult with committee chairs, House Democratic leadership, and the party caucus before making a public statement later later that afternoon.

Although the majority of House Democrats now support an impeachment inquiry—a number growing seemingly by the minute—the question of Trump’s potential removal from office lies with the Republican-held Senate. There leadership has been much quieter on the question of impeachment.

Asked on Tuesday if he would take up articles of impeachment if the House did the same, Majority Leader Mitch McConnell called the question “quite premature.”