US Democrats yesterday pressed the Republican-controlled Senate to call Donald Trump's top lieutenants to testify in its trial of the impeached president, as they sought to focus attention on the trial ahead of the 2020 presidential election.

A day after the Democratic-led US House of Representatives impeached Trump (photo), Speaker Nancy Pelosi said she would not formally hand off impeachment to the Senate until she got a sense of how Senate Republican Leader Mitch McConnell would manage the trial.

"We're ready when we see what they have," she told a news conference.

Pelosi was not expected to move until lawmakers return from their year-end recess in early January, according to aides.

That did not seem to bother McConnell, who said the two sides were at an impasse.

"I'm not sure what leverage there is in refraining from sending us something we do not want," he said on the Senate floor.

The impeachment effort has deepened the partisan divide in Washington, and polls show that public opinion has hardened along ideological lines as well.

One surprise came when Christianity Today, a prominent evangelical publication, called Trump's conduct "profoundly immoral" and said he should be removed from office.

Polls have found that white evangelical Christians are among Trump's most loyal supporters.

Trump has denied wrongdoing and called the impeachment inquiry launched by Pelosi in September a "witch hunt."

His political future now rests with 77-year-old McConnell (above), a self-proclaimed "Grim Reaper" who is widely known as a shrewd negotiator who plays hardball politics at a level unusual even by Washington standards.

Democrats want McConnell to allow top Trump aides like Mick Mulvaney, the White House acting chief of staff, and John Bolton, Trump's former national security advisor, to testify, according to a senior Democratic aide.

"Is the president's case so weak that none of the president's men can defend him under oath?" asked Senate Democratic Leader Chuck Schumer, who later urged McConnell in a meeting to use the two-week recess to consider allowing witnesses.

In an interview on MSNBC, Schumer said he doubted McConnell would agree to allow witness testimony. But Schumer said he believed enough Republican senators would join all the Democrats in forcing the adoption of rules for the trial that would include having witnesses testify.

In a historic vote on Wednesday evening, House Democrats impeached Trump for alleged abuse of power and obstruction of Congress related to his attempts to pressure Ukraine to investigate Democratic political foe Joe Biden. He is only the third US president to be impeached.

The Senate trial is expected in early January. Trump himself has expressed an interest in a long trial with witnesses, but senior Republican senators want to put the affair behind them. They point out that there were no live witnesses at the 1999 impeachment trial of Democratic then-president Bill Clinton.

McConnell and Schumer met yesterday afternoon. Asked how he felt about Pelosi potentially withholding the articles of impeachment, the Republican said: "If the speaker wants to hold on to them, it’s fine with us."

Earlier, McConnell accused Democrats of succumbing to "transient passions and factionalism" and made it clear that he did not think the Senate should find Trump guilty.

"The vote did not reflect what had been proven. It only reflects how they feel about the president. The Senate must put this right," McConnell said on the Senate floor.

Working with the White House

Trump, 73, is accused of abusing his power by pressuring Ukraine to investigate Biden (below), a former US vice-president, as well as a discredited theory that Democrats conspired with Ukraine to meddle in the 2016 election.

Democrats say that as part of his pressure campaign, Trump held back US$391 million in security aid for Ukraine and a coveted White House meeting for Ukrainian President Volodymyr Zelenskiy as leverage to coerce Kiev into interfering in the 2020 election by smearing Biden.

Trump is also accused of obstruction of Congress for directing administration officials and agencies not to cooperate with the impeachment inquiry.

A Senate trial would kick off a politically-charged year heading into the presidential election, which will pit Trump against one of a field of Democratic contenders, including Biden, who has repeatedly criticised the president's conduct in office.

Fewer than half of Americans want Trump removed from office, according to a Reuters/Ipsos poll released yesterday.

The Senate is highly unlikely to find Trump guilty and remove him from office. At least 20 Republican senators would have to vote to convict Trump and none has indicated a willingness to do so.

McConnell has said he is working in tandem with the White House on trial preparations, drawing accusations from Democrats that he is ignoring his duty to consider the evidence in an impartial manner.

Asked about his strategy, Trump told reporters at the White House: "We have great senators - Republican senators. ... I'm going to let them decide what to do. That's going to be up to them."

Pelosi said she would wait to name the Democratic House "managers," who will prosecute the case until she knew more about the Senate trial procedures. The chamber's No 3 Democrat, James Clyburn, told CNN the House could wait indefinitely.

Pelosi's tactic gives Democrats time to convince some Senate Republicans that they should hear from witnesses, said Democratic Senator Chris Van Hollen.

"When you have a trial you get to call witnesses," he told Reuters.

- Reuters