Details of President Trump Donald John TrumpFederal prosecutor speaks out, says Barr 'has brought shame' on Justice Dept. Former Pence aide: White House staffers discussed Trump refusing to leave office Progressive group buys domain name of Trump's No. 1 Supreme Court pick MORE's phone conversation with Ukrainian President Volodymyr Zelensky, in which he pressed for an investigation into former Vice President Joe Biden Joe BidenFormer Pence aide: White House staffers discussed Trump refusing to leave office Progressive group buys domain name of Trump's No. 1 Supreme Court pick Bloomberg rolls out M ad buy to boost Biden in Florida MORE, have led to a flurry of calls for an impeachment inquiry.

Much of that activity has taken place in the House, where Speaker Nancy Pelosi Nancy PelosiDemocratic senator to party: 'A little message discipline wouldn't kill us' Overnight Health Care: New wave of COVID-19 cases builds in US | Florida to lift all coronavirus restrictions on restaurants, bars | Trump stirs questions with 0 drug coupon plan Overnight Defense: Appeals court revives House lawsuit against military funding for border wall | Dems push for limits on transferring military gear to police | Lawmakers ask for IG probe into Pentagon's use of COVID-19 funds MORE (D-Calif.) on Tuesday announced a formal impeachment inquiry, but several previous holdouts in the Senate have also joined the chorus.

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Others like Sens. Kamala Harris Kamala HarrisTexas Democratic official urges Biden to visit state: 'I thought he had his own plane' The Hill's Campaign Report: Biden on Trump: 'He'll leave' l GOP laywers brush off Trump's election remarks l Obama's endorsements A game theorist's advice to President Trump on filling the Supreme Court seat MORE (Calif.), Amy Klobuchar Amy Klobuchar3 reasons why Biden is misreading the politics of court packing Social media platforms put muscle into National Voter Registration Day Battle lines drawn on precedent in Supreme Court fight MORE (Minn.) and Elizabeth Warren Elizabeth WarrenOvernight Defense: Appeals court revives House lawsuit against military funding for border wall | Dems push for limits on transferring military gear to police | Lawmakers ask for IG probe into Pentagon's use of COVID-19 funds On The Money: Half of states deplete funds for Trump's 0 unemployment expansion | EU appealing ruling in Apple tax case | House Democrats include more aid for airlines in coronavirus package Warren, Khanna request IG investigation into Pentagon's use of coronavirus funds MORE have been calling for impeachment action since before the Ukraine news.

Here are the Senate Democrats who have called for an impeachment or an inquiry this week.

Senate Minority Leader Charles Schumer Chuck SchumerPelosi slams Trump executive order on pre-existing conditions: It 'isn't worth the paper it's signed on' 3 reasons why Biden is misreading the politics of court packing Cruz blocks amended resolution honoring Ginsburg over language about her dying wish MORE (N.Y.)

Schumer announced on Wednesday that he supported Pelosi’s impeachment inquiry.

"I strongly support Speaker Pelosi’s decision. If we don’t reckon with President Trump’s persistent transgressions, the very foundation of this great republic is at risk," Schumer said. "The president kept pushing and pushing and pushing the constitutional envelope. Finally, the president’s conduct made an impeachment inquiry unavoidable.”

"I know she did not make this decision lightly and took no pleasure in making it,” he added. “It is her carefully considered judgment that it is now in the best interest of our country and our Constitution to proceed with an impeachment inquiry.”

Sen. Dick Durbin Richard (Dick) Joseph DurbinThe Hill's Morning Report - Sponsored by Facebook - Trump previews SCOTUS nominee as 'totally brilliant' Feinstein 'surprised and taken aback' by suggestion she's not up for Supreme Court fight Grand jury charges no officers in Breonna Taylor death MORE (Ill.)

Before Schumer’s statement, Durbin was the highest-ranking Senate Democrat to endorse an impeachment inquiry.

“I think this may be the straw that broke the camel’s back,” the Senate Democratic whip said Tuesday. “There’s so much cumulative evidence here and many of us have wondered if this would ever see the light of day in an impeachment inquiry. But I think now we have to move forward.”

Sen. Bob Casey Robert (Bob) Patrick CaseySecond GOP senator to quarantine after exposure to coronavirus GAO report finds brokers offered false info on coverage for pre-existing conditions Catholic group launches .7M campaign against Biden targeting swing-state voters MORE (Pa.)

Casey is the most recent senator to call for impeachment proceedings, and he's one of the most moderate Senate Democrats to do so.

“Given this clear abuse of power, I believe I have an obligation to outline the conduct, both during the Russian investigation and the Ukraine matter, that is within the well-established definition of the ‘high crimes and misdemeanors’ that the Senate would consider in an impeachment trial,” he said in a statement Wednesday afternoon.

“Surely, not every instance of presidential wrongdoing merits impeachment. Using the vast powers of impeachment in a cavalier fashion would be an insult to our Constitution,” Casey added. “However, a failure by Congress to pursue impeachment in the face of grave offenses by the President is just as insulting to our Constitution and our values.”

Sen. Chris Murphy Christopher (Chris) Scott MurphyDemocratic senator calls for 'more flexible' medical supply chain to counter pandemics The Hill's 12:30 Report - Presented by Facebook - Don't expect a government check anytime soon GOP chairman to release interim report on Biden probe 'in about a week' MORE (Conn.)

Murphy announced his support for an impeachment inquiry Tuesday, saying, “It is now my belief that the House of Representatives must begin an impeachment inquiry into the president’s corrupt efforts to press a foreign nation into the service of his reelection campaign.”

Murphy had been sharply critical of the handling of the whistleblower report before coming out in favor of an impeachment inquiry, particularly after Sen. John Cornyn John CornynHillicon Valley: Productivity, fatigue, cybersecurity emerge as top concerns amid pandemic | Facebook critics launch alternative oversight board | Google to temporarily bar election ads after polls close Lawmakers introduce legislation to boost cybersecurity of local governments, small businesses On The Trail: Making sense of this week's polling tsunami MORE (R-Texas) questioned whether the whistleblower was a “leaker.”

"This is just a head shaking moment for me that Republicans don't give a damn about the national security of this country and are willing to let the president get away with this fundamental corruption," Murphy said Monday. "If that is the direction that they take—attacking the whistleblower, trying to cover up this corruption, it's a really, really sad day for the country."

Sen. Richard Blumenthal (Conn.)

Blumenthal on Tuesday morning called for the House to form an impeachment committee, hours before Pelosi announced the inquiry.

“I am calling today for a House Select Committee to investigate and move forward with impeachment proceedings against the President. I reached this decision with sadness, but also anger,” Blumenthal said in a statement.

“Congress must demand accountability," he added. "At this moment, the threat to the rule of law and our democracy has reached a new height and requires all of us to step forward.”

Sen. Chris van Hollen (Md.)

Van Hollen announced his support for an impeachment inquiry Tuesday shortly before Pelosi’s announcement.

“As the White House continues to prevent the House of Representatives from exercising their Constitutionally-mandated oversight role, it has become clear that the tools provided by an impeachment inquiry must be employed,” van Hollen said in a statement.

“I have not come to this decision lightly — and I regret that the President’s actions require these measures. But the American people deserve the truth and confidence in their government, and I support an impeachment inquiry in order to expose the facts and protect our democracy,” he added.

Sen. Tina Smith Tina Flint SmithThe Hill's Campaign Report: Trump faces backlash after not committing to peaceful transition of power Credit union group to spend million on Senate, House races Health officials tell public to trust in science MORE (Minn.)

Smith struck a cautious note in her endorsement of an impeachment inquiry Tuesday, noting in a statement that impeachment is not the same as removal from office, which would meet a dead end in the GOP-controlled Senate.

“Impeachment is the only way in our system of constitutional checks and balances to establish whether a President has abused his power and put his own interests ahead of our national security and the rule of law,” Smith said in a statement.

“My job as Senator is to uphold the Constitution and the rule of law, and I must fulfill my responsibility to listen to all the evidence before making a final judgment,” she added.

Sen. Brian Schatz Brian Emanuel SchatzDemocratic senator to party: 'A little message discipline wouldn't kill us' CDC causes new storm by pulling coronavirus guidance Overnight Health Care: CDC pulls revised guidance on coronavirus | Government watchdog finds supply shortages are harming US response | As virus pummels US, Europe sees its own spike MORE (Hawaii)

Schatz called for impeachment on Monday.

“[Trump] and his legal team argue that a sitting president’s authorities are so vast that they literally transcend the law. They argue that the Congress has a remedy for this criminality and defiance – the impeachment process,” Schatz said in a statement Monday.

“If that is their view, so be it. On behalf of the people who elected us, we must formalize and accelerate the impeachment process so that Congress, by exercising its responsibility under Article 1 of the Constitution, can provide some measure of accountability,” he added.

Updated at 7:23 p.m.