Democratic presidential candidate and former Vice President Joe Biden puts on a Beau Biden Foundation hat while speaking at the Polk County Democrats Steak Fry, in Des Moines, Iowa, Saturday, Sept. 21, 2019. Credit: Nati Harnik | AP

Former vice president Joe Biden called for Congress to begin impeachment of President Donald Trump if the White House continues to stonewall Congress’s investigations, including new questions regarding reports that Trump asked the Ukrainian president to investigate Biden and his son, Hunter.

“I can take the political attacks. They’ll come and they’ll go and, in time, they’ll soon be forgotten. But if we allow a president to get away with shredding the United States Constitution, that will last forever,” Biden said in brief remarks Tuesday afternoon in Wilmington, Delaware.

Biden, who spoke for only several minutes and left without taking questions, said if Trump doesn’t comply with Congress, it’ll be forced to begin impeachment. Biden said it would be “a tragedy, but a tragedy of (Trump’s) own making.”

Biden’s remarks fall short of asking for impeachment to begin now. Congress has many concurrent investigations into Trump, his administration, his campaign and his private businesses. The White House has defied subpoenas for testimony and documents.

The news of Trump’s conversation with the Ukrainian president has prompted a flood of congressional Democrats who had been on the fence about impeachment to come out in favor of starting that process.

Despite being at the center of this latest controversy, Biden is mostly alone in the 2020 Democratic presidential field in not explicitly calling for the House to begin an impeachment inquiry.

“We appear to have a president who unbelievably, may have used security funds – funds designed to protect the security of the people of the United States – as a means to gain political dirt on an opponent,” Sen. Bernie Sanders, I-Vermont, said at a campaign stop in Davenport, Iowa, calling for the House to begin impeachment now.

Sen. Elizabeth Warren, D-Mass., was the first of the 2020 candidates to do so following the release of then special counsel Robert Mueller’s Russia investigation report.

“I called for impeachment five months ago, the day after the Mueller report came out. Trump continues to commit crimes because he believes he’s above the law. If Congress does nothing to respond, he’ll be right. We must begin impeachment proceedings – now,” Warren tweeted Tuesday.

South Bend, Indiana, Mayor Pete Buttigieg, who has been more cautious around the question of impeachment, told MSNBC on Monday that Trump has “made it clear he deserves to be impeached” after the most recent reports of his conversation with Ukrainian President Volodymyr Zelensky.

A whistleblower within the intelligence agency filed a complaint with its inspector general alleging that Trump had made an inappropriate ask of the Ukrainian president during a July phone conversation. Trump, who had put a hold on military aid for Ukraine about a week before the call, allegedly brought up Biden’s role in pressuring the firing of a top prosecutor in Ukraine in 2016 and suggested Biden did so on behalf of his son.

Biden’s son, Hunter, sat on a board of a Ukrainian gas company that had been investigated by the prosecutor. Biden’s efforts to get the prosecutor removed, however, was related to the Obama administration’s belief that the prosecutor was ineffective at rooting out corruption in Ukraine.

Trump said Tuesday that he did withhold the aid as a way to put pressure on other nations to contribute more to Ukraine. He had previously suggested he’d held back funds over concerns about corruption in the country.

The Washington Post’s Matt Viser and Sean Sullivan contributed to this story.