Washington, October 31: US President Donald Trump called on Republicans to rally behind him Thursday as Democrats in Congress prepared to move the impeachment investigation against him into higher gear with public hearings.

The US leader faced the increasing likelihood of becoming the third president in history to be impeached and placed on trial for removal in the Senate over an alleged extortion scheme to obtain Ukraine's help to get him reelected in 2020.

The president retweeted a rallying cry from Fox News host Laura Ingraham that called on Republicans to "stand together and defend the leader of their party against these smears."

"This farce should never be allowed to roll into a winter showtrial. Indeed, allowing a long, drawn out trial in the Senate would merely validate and perpetuate the fraud begun in the House," read the tweet.

- Holding Trump 'accountable' -

Trump is accused of withholding military aid to compel Ukraine to mount an embarrassing corruption probe against his Democratic election rival Joe Biden -- using US foreign policy in an illegal shakedown for his personal political benefit.

Trump dismisses the case as cooked up, but congressional investigators have heard a steady flow of corroborating evidence from government officials testifying behind closed doors on Capitol Hill.

The party call-to-arms came just hours before Democrats were to ram through the House legislation that would move the inquiry into the public eye -- giving Americans the chance to hear on live television the evidence against him.

The next phase will see open evidentiary hearings in the House Intelligence Committee, which has led the inquiry so far, presenting witnesses and documentary evidence and allowing Republicans to challenge the evidence.

The case would then go to the House Judiciary Committee, where Trump and his lawyers will be able to challenge the evidence and submit their own.

If the case against Trump is deemed strong enough, the committee will draw up formal charges against the president -- articles of impeachment -- to be voted on by the entire House.

That process could be completed within the final months of this year. The Democrat-controlled House is expected to pass the articles, which would then see Trump go on trial for removal in the Senate, where Republicans have a majority.

"We are not here in some partisan exercise. We are here because the facts compel us to be here," said Jim McGovern, Chairman of the House Rules Committee which drew up the impeachment process legislation.

"There is serious evidence that President Trump may have violated the Constitution. This is about protecting our national security and safeguarding our elections," he said on the house floor.

"If we don't hold this president accountable, we could be ceding our ability to hold any president accountable,:" he said.

- Witnesses back of 'quid pro quo' allegation -

Nearly a dozen witnesses so far have confirmed in House interviews the accusations that in a concerted effort with top aides and his personal lawyer, Trump pressured Ukraine to help his reelection effort in 2020 by producing dirt on Biden, the former vice president.

The allegations focus on a July 25 phone call in which Trump pressed Ukraine President Volodymyr Zelensky to open investigations into Biden and Biden's son, who had close ties to a Ukraine energy firm.

Asking for a "favor" in the same call, Trump also pushed Zelensky to for an investigation to find evidence in support of conspiracy theories that hold that Kiev assisted Democrats against Trump in the 2016 election.

Early Thursday Tim Morrison, the White House National Security Council's top Russia expert, arrived on Capitol Hill for his testimony.

According to other witnesses, Morrison, who resigned late Wednesday, has personal knowledge of the White House's effort to freeze $391 million in military aid to Ukraine to pressure Zelensky to launch the political investigations.

The investigators also have called on Trump's estranged former national security advisor John Bolton to testify next week, along with two White House national security lawyers.

Bolton, other witnesses have said, disagreed strongly with Trump's tactics toward Ukraine and the involvement of his personal lawyer Rudy Giuliani in Ukraine policy.

(The above story first appeared on LatestLY on Oct 31, 2019 08:25 PM IST. For more news and updates on politics, world, sports, entertainment and lifestyle, log on to our website latestly.com).