Biden: Possible impeachment 'tragedy' of Trump's own making Biden urged the president to comply with congressional requests.

Former Vice President Joe Biden, in his most direct statement yet on the topic, called on President Trump to comply with all of Congress’ outstanding, lawful requests for information related to his phone call with Ukraine's president and cautioned that if Trump does not, Congress has no choice but to impeach.

If "the president does not comply with such a request to the Congress, he continues to obstruct congress and flaunt the law. Donald Trump will leave congress in my view no choice but to initiate impeachment," Biden told reporters Tuesday in Wilmington, Delaware.

Biden told the gathering that he can "take the political attacks" but cautioned that "if we allow a president to get away with shredding the U.S constitution, that will last forever."

Impeachment, Biden said "would be a tragedy, but a tragedy of his own making."

Trump promised to release on Wednesday an unredacted transcript of his phone call with Ukraine's president that has triggered a new Democratic push for impeachment, just hours before House Speaker Nancy Pelosi announced she was moving forward with a formal impeachment inquiry into Trump.

The former vice president has hedged previously on the issue, never explicitly joining calls to remove Trump.

The fast-moving developments come amid questions about whether Trump had made aid to Ukraine contingent on Ukraine's President Volodymyr Zelensky agreeing to investigate Biden and his son, Hunter. Trump, who had said previously he was concerned about sending aid to Ukraine because of corruption he alleged there, gave a new explanation Tuesday saying he ordered the aid frozen – before the call – because he was unhappy with how much European countries were contributing to Ukraine.

Over the past 24 hours, a rapid succession of Democrats have embraced impeachment. House Speaker Nancy Pelosi and her caucus were on the brink of going forward Tuesday, with at least 160 Democrats – more than two-thirds of the caucus - now publicly supporting impeaching President Trump. The full Senate – both Republicans and Democrats – passed a non-binding resolution calling on the Trump administration to release the secret whistleblower complaint to Congressional Intelligence Committees.

Supporters are seeking an impeachment inquiry since the recent whistleblower complaint about President Trump's phone call with the Ukranian president and reports he pressured the foreign leader to investigate the Democratic rival, something Trump denies although he's said they discussed it. Those supporting impeachment include several prominent committee chairs and freshman Democrats from formerly GOP-held congressional districts that Pelosi was trying to shield from impeachment pressure if it would make them vulnerable when facing reelection.

So far, 11 Democrats presidential candidates have explicitly called for impeachment, a list which includes: New Jersey Sen. Cory Booker, California Sen. Kamala Harris, Minnesota Sen. Amy Klobuchar, former Texas Rep. Beto O’Rourke, Massachusetts Sen. Elizabeth Warren, former Housing and Urban Development Secretary Julian Castro, Miramar, Florida Mayor Wayne Messam, Ohio Rep. Tim Ryan, Vermont Sen. Bernie Sanders, Marianne Williamson, a motivational speaker and billionaire Tom Steyer.

Warren was one of the first to call for impeachment.

South Bend, Ind. Mayor Pete Buttigieg shifted his position Monday, going further by saying he supports "the House on taking on impeachment proceedings.

However, one of the two candidates who, as a House member, would actually get a vote on impeachment – Hawaii Rep. Tulsi Gabbard, is not on board, and thinks it would be “terribly divisive.”