Sen. Cory Booker on Wednesday called on Congress to "immediately" begin impeachment proceedings against President Donald Trump, adding to a fast-growing chorus of 2020 Democratic presidential candidates.
The New Jersey senator, who'd previously said it was too soon to talk about removing the president, tweeted that "Robert Mueller's statement makes it clear: Congress has a legal and moral obligation to begin impeachment proceedings immediately."
"I've been asking for Mueller’s testimony — today he made his views clear," Booker added.
Pete Buttigieg, who previously said he thought it was time for Democrats in the House to start moving toward impeachment, also came out more forcefully after Mueller spoke at the Justice Department saying it's Congress's role to accuse a president of wrongdoing.
"The message really is, 'Over to you, Congress,'" the South Bend, Ind., mayor told NBC News in an exclusive interview.
"What he reminded everyone was he's part of a DOJ that says you can't, which means his option wasn't charge or don't charge," he said. "But procedures do exist for a sitting president to be held accountable, and if the Justice Department can't charge a sitting president with an actual crime, then it goes over to Congress to decide whether to charge the president with a high crime. This is as close to an impeachment referral as you could get under the circumstances."
Sen. Kamala Harris also interpreted Mueller's statement as an "impeachment referral."
"We need to start impeachment proceedings. It's our constitutional obligation," Harris tweeted.
"I think it’s a fair inference from that press conference that Bob Mueller was referring impeachment to the United States Congress," she told NBC News before an event in South Carolina.
"We have got to now let the process start its course around Congress acting on what we know is essentially indictable evidence and information."
Sen. Kirsten Gillibrand also joined in the calls. "The White House has repeatedly stonewalled Congress' ability to take basic fact-finding steps," she said in a statement. "That fact, combined with Mueller's clear message today, tells me that Republicans and Democrats should begin impeachment hearings."
The current front-runner in the polls, former Vice President Joe Biden, was standing by his earlier stance that Congress should continue investigating. Campaign spokesman TJ Ducklo said Biden agrees with House Speaker Nancy Pelosi "that no one would relish what would certainly be a divisive impeachment process, but that it may be unavoidable if this administration continues on its path."
Sen. Bernie Sanders maintained his position as well, saying Congress "must continue its investigations."
"If the House Judiciary Committee deems it necessary, I will support their decision to open an impeachment inquiry," Sanders (I-Vt.) tweeted. Sen. Amy Klobuchar issued a similar statement, while pushing her two bills to help secure elections from foreign interference.
Sen. Elizabeth Warren — among the first of the candidates to call for Trump to be impeached after Mueller's report was released last month — said on Wednesday "it's up to Congress to act."
Julian Castro, the former housing secretary and another of the initial candidates to call for impeachment, told MSNBC that Mueller "made it even more clear that he's laying this at the lap of Congress to go forward," and "it's a mistake not to go forward with impeachment."
His fellow Texan, former Rep. Beto O'Rourke, tweeted, "There must be consequences, accountability, and justice. The only way to ensure that is to begin impeachment proceedings."
Rep. Seth Moulton, who's supported calls for impeachment proceedings in the past, tweeted those hearings "should begin tomorrow." "Mueller did his job. Now it's time to do ours," the Massachusetts congressman and presidential contender wrote.
Rep. Eric Swalwell has also called for impeachment proceedings, but the California Democrat and 2020 hopeful said in an interview on MSNBC that if he were elected president, he'd do away with the DOJ policy that says a commander-in-chief cannot be indicted while's he's in office.
"If I win, day one, I will tell the DOJ to lift that policy. I hope every Democratic nominee makes that pledge," Swalwell said. "No president should be immunized in the way that this president has been immunized because he would be indicted right now, is what the Special Counsel told us."