Updated at 6:30 p.m. ET
The House of Representatives has delivered articles of impeachment against President Trump to the Senate, which is expected to begin a trial next week.
Earlier in the day, House Speaker Nancy Pelosi named seven Democratic members of Congress as the managers who will argue the case for impeachment.
Those managers brought the articles to the Senate on Wednesday evening.
"What is at stake here is the Constitution of the United States," Pelosi said in a press conference announcing the managers.
Pelosi appointed Reps. Adam Schiff, Jerry Nadler, Zoe Lofgren, Val Demings, Hakeem Jeffries, Sylvia Garcia and Jason Crow. Pelosi said Schiff will take the lead.
"The emphasis is on litigators. The emphasis is on comfort level in the courtroom. The emphasis is making the strongest possible case to protect and defend our Constitution, to seek the truth for the American people," Pelosi said in a Wednesday press conference.
The House voted earlier in the day on a resolution to transmit the articles and confirm the impeachment managers. It was 228-193, largely along party lines.
"This is as serious as it gets for any of us," Pelosi said on the House floor. But House Minority Leader Kevin McCarthy, R-Calif., called impeachment "a blunder" and "not a moment this body should be proud of."
The seven managers bring a diverse range of experience. Schiff and Nadler led the impeachment process in the House. Lofgren is taking part in her third impeachment process; she was a staffer when the House Judiciary Committee voted out articles of impeachment against President Richard Nixon, and a committee member during President Bill Clinton's and Trump's impeachment. Demings is a former Orlando chief of police and is also a member of the House intelligence committee; Garcia is a former Houston municipal judge; Jeffries is a former corporate lawyer; and Crow is a former Army Ranger who served in Iraq and Afghanistan and was a co-author of a letter making the case for Congress to begin impeachment proceedings.
Abuse of power, obstruction of Congress
Pelosi accused Trump of using the congressional appropriations process "as his private ATM machine to grant or withhold funds granted by Congress in order to advance his personal and political advantage," referencing the White House's hold on defense aid to Ukraine even though the funds had been appropriated by Congress.
The president's defenders argue the money was held up because of concerns over political corruption in Ukraine.
Wednesday's actions come a month after the House approved two articles of impeachment against the president, charging him with abusing the powers of his office by attempting to pressure the government of Ukraine to investigate potential political opponent Joe Biden and his son's activities there and with obstructing Congress by refusing to cooperate in its investigation.
Trump denies any wrongdoing and has excoriated the process. The White House reiterated its position following the House's vote on Wednesday.
"These are the weakest articles of impeachment that have ever been passed," a senior administration official told reporters on a background call. The official said there was no violation of law listed among the articles of impeachment. "We think these articles fail on their face."
Seeking a fair trial
With the formal handover, Senate Majority Leader Mitch McConnell takes the reins from Pelosi. He is establishing rules for the trial that his chamber will vote on.
White House press secretary Stephanie Grisham said on Wednesday that Trump "looks forward to having the due process rights in the Senate that Speaker Pelosi and House Democrats denied to him, and expects to be fully exonerated."
The exact ground rules for Trump's trial remain unclear. Democrats have demanded that the Senate call additional witnesses, potentially including former national security adviser John Bolton, who has said he is willing to testify if subpoenaed. But McConnell has resisted, saying Tuesday that the "more contentious issue" of calling witnesses will be addressed later.
"The Senate is on trial as well as the president," Nadler said after being named one of the House impeachment managers. "Does the Senate conduct a trial according to the Constitution, to vindicate the republic, or does the Senate participate in the president's crimes by covering them up?"
McConnell has sought to adhere to the procedure established in the Clinton impeachment trial in 1998, which allowed for a vote to dismiss the charges, as well as a vote on hearing additional testimony once opening arguments were made.
Trump has sought to have the Senate dismiss the charges, arguing that he did nothing wrong, but McConnell said Tuesday, "There is little to no sentiment in the Republican conference for a motion to dismiss."
Next steps ahead of the trial
On Thursday, the impeachment managers are expected to read the House resolution that appointed them as well as the articles of impeachment in full – on the Senate floor.
Later in the day, Chief Justice John Roberts, who will preside over the trial, will be sworn in by Sen. Chuck Grassley, R-Iowa — Senate president pro tempore. Roberts would then swear in all 100 senators as jurors. After this, the president is summoned and given time to respond.
On Tuesday, McConnell plans to have the Senate vote on rules for the trial. Then he says, the trial will begin "in earnest."
The senior administration official told reporters on Wednesday that the trial is unlikely to last longer than two weeks.
With Republicans holding a 53-47 majority in the Senate, and 67 votes necessary to convict Trump, it is almost certain the president will be acquitted.
The congressional proceedings mark just the third time in U.S. history that a president will be tried and face potential removal from office by the Senate. Presidents Andrew Johnson and Clinton were acquitted by the Senate after impeachment by the House.