WASHINGTON (REUTERS) - United States Senate Majority Leader Mitch McConnell raised the prospect on Tuesday (Dec 10) of a short Senate impeachment trial for President Donald Trump in which no witnesses would be called.

The scenario of a truncated trial would put Mr McConnell, the top Senate Republican, at odds with Mr Trump, also a Republican, who has been calling for a full trial with witnesses, including former vice-president Joe Biden, on the Senate floor.

The Democratic-controlled House of Representatives is expected to vote to impeach Mr Trump next week after unveiling formal charges against him on Tuesday.

The charges accuse Mr Trump of "betraying" the country by abusing power in an effort to pressure Ukraine to probe Mr Biden, a 2020 Democratic presidential contender, and then obstructing Congress' investigation into the scandal.

Mr Trump has denied any wrongdoing and has made the Democratic-led impeachment inquiry a rallying cry for his supporters as he attempts to win re-election next November.

Mr McConnell stressed in remarks to reporters that no decisions had been made on how a trial would proceed if the House approves articles of impeachment against Mr Trump.

He said any trial would begin with House Democrats making their case for finding the President guilty, followed by White House lawyers arguing for an acquittal.

At that point, he said, the Senate "could go down the path of calling witnesses and basically having another trial".

Or, he said, 51 senators could come together, which would be a majority of the 100 senators, and decide "that they've heard enough and they believe they know what would happen and could move to vote on the two articles of impeachment sent over to us by the House".

Senate Democratic leader Chuck Schumer has said he hopes for a "full" and "open" trial that is not cut short.

One long-time Republican strategist said it would be difficult for Mr McConnell and Mr Schumer to engage in serious negotiations on trial rules at least until the House approves the articles of impeachment.

Any negotiation, the strategist added, could spark a high-stakes battle over the witnesses that could be called by each side.

There are 53 Republican senators, 45 Democrats and two independents who regularly align with Democrats.

Two-thirds of the Senate, or at least 67 if all 100 are present, are needed to find a president guilty of impeachment charges and remove him from the White House.

No Senate Republicans have indicated so far that they are considering such a move.

'NEED FULL TRIAL'

While Mr Trump has repeatedly called the House Democrats' impeachment investigation a "witch hunt", he also has called for a trial with witnesses testifying.

In a tweet on Dec 5, he wrote: "We will have Schiff, the Bidens, Pelosi and many more testify."

He was referring to House Intelligence Committee Chairman Adam Schiff, Mr Biden, his son Hunter and House Speaker Nancy Pelosi, all of whom are Democrats.

Last week, Mr Trump dispatched his top White House lawyers to attend a lunch with Senate Republicans to discuss the possible impeachment trial.

White House legislative liaison Eric Ueland told reporters after that meeting that in order for Mr Trump to make an effective case to the Senate, "we need both a full trial and the opportunity to call witnesses", pointing to the Senate chamber.

A long Senate trial could delay the chamber's approval of a US-Mexico-Canada trade agreement known as USMCA, which would replace the North American Free Trade Agreement, and detract from Republican senators' campaign message of a strong US economy as some of them seek re-election next year.

During Democratic president Bill Clinton's 1999 impeachment trial, no witnesses testified on the Senate floor.

Instead, videotaped depositions were done with just a few witnesses, which senators could screen privately.

Mr Clinton was acquitted in the Senate on charges arising from his sexual relationship with a White House intern.