By David Morgan and Richard Cowan
WASHINGTON (Reuters) - The Democratic-led U.S. House of Representatives will vote on Wednesday to send formal impeachment charges against President Donald Trump to the Senate, lawmakers said on Tuesday, clearing the way for a trial set to begin in earnest early next week.
House Speaker Nancy Pelosi told a party meeting that she would also name the Democrats' team of "managers" who will lead the prosecution of Trump at the trial, Democratic congressman Henry Cuellar said.
Trump became only the third U.S. president to be impeached when the House last month approved charges that he abused his power by pressuring Ukraine to announce an investigation into Democratic rival Joe Biden and obstructed Congress.
Pelosi has delayed sending the charges to the Senate in an unsuccessful effort to get that chamber's Republican Majority Leader Mitch McConnell to agree to include new witness testimony that could be damaging to the Republican president.
The Senate is expected to acquit Trump, as none of its 53 Republicans have voiced support for ousting him, a step that would require a two-thirds majority in the 100-member Senate.
A Wednesday House vote would allow the Senate to begin considering the charges against Trump next week, McConnell said. The chamber will first tackle housekeeping duties, such as swearing in members and formally reading the two impeachment charges later this week, he said.
"We're assuming we're on the trial next Tuesday and I think that's the case," he told a news conference.
Among practical issues the Senate will consider this week are decisions on who is allowed onto the floor of the chamber during the trial and the placement of furniture to allow a trial setup.
All the U.S. senators present will act as the jury at the trial, which will be overseen by the head of the Supreme Court, Chief Justice John Roberts. A clash over Democrats' efforts to introduce new witnesses and documents as evidence will likely dominate the early part of the trial.
"If you want the truth, you have to have witnesses, you have to have documents," the top Democratic senator, Chuck Schumer, told reporters. "The president and the American people deserve nothing more than a fair, full, honest process," he said.
Trump has denied any wrongdoing and has dismissed his impeachment as a partisan bid to undo his 2016 election win as he tries to win re-election in November.
The White House said on Tuesday the trial was "purely political."
"It's out of a desire to gain more power. It has nothing to do with the rule of law by any stretch because the articles they came up with don't actually cite any crime. It's just to try and smear this president because they know they can't beat him at the ballot box," White House spokesman Hogan Gidley told Fox News.
The case against Trump is focused on a July 25 telephone call in which he asked Ukrainian President Volodymyr Zelenskiy to open a corruption investigation into former Vice President Biden and his son Hunter, and into a discredited theory that Ukraine, not Russia, meddled in the 2016 U.S. election.
Democrats say Trump abused his power by asking a foreign government to interfere in an American election for his own political benefit at the expense of U.S. national security.
Joe Biden, whose son served on the board of a Ukrainian gas company, is a leading candidate for the Democratic presidential nomination to face Trump in the Nov. 3 election.
The two articles of impeachment - or formal charges - against Trump include an accusation that he obstructed Congress' efforts to investigate him by instructing officials to ignore House committee subpoenas to testify or to produce documents at an earlier stage of the Ukraine investigation.
Democrats want to hear at the trial from current and former White House officials, such as former national security adviser John Bolton, for insight into Trump's pressure campaign on Ukraine that could be damaging for the president's defense.
McConnell said the chamber will hold a vote to decide whether to call witnesses at all. If that succeeds, he said Republicans likely will want to call witnesses of their own.
Pelosi could name up to 10 lawmakers as managers to argue the case against Trump, including House Intelligence Committee Chairman Adam Schiff, who spearheaded the impeachment probe, and House Judiciary Committee Chairman Jerrold Nadler.
The 1999 impeachment trial of then-President Bill Clinton lasted five weeks. If the Senate conducts its trial along those lines, as McConnell has suggested, that would mean lawmakers would still be considering charges against the president while the first nominating contests of the 2020 presidential election were underway in Iowa and New Hampshire.
That could make life difficult for the four senators who are running for the Democratic nomination: Elizabeth Warren, Michael Bennet, Amy Klobuchar and Bernie Sanders.
Republicans presume Biden would have been damaged politically by a Ukrainian probe into him and his son, but Trump and his allies have offered no evidence that they were involved in corruption in Ukraine.
A U.S. cybersecurity firm said on Monday that Russian military hackers tried to steal emails from the Ukrainian energy firm Burisma where Hunter Biden was on the board.
No U.S. president has been removed as a direct result of impeachment. Richard Nixon resigned in 1974 before he could be removed, while Andrew Johnson and Bill Clinton were impeached by the House, respectively in 1868 and 1998, but not convicted by the Senate.
(Reporting by David Morgan and Richard Cowan; Additional repoirting by Doina Chiacu and Susan Cornwell; Writing by Alistair Bell; Editing by Andy Sullivan, Jonathan Oatis and Bill Berkrot)