John Roberts (right) is being sworn in to preside over impeachment trial of Donald Trump at the US Capitol in Washington on Thursday. Reuters

US Supreme Court's Chief Justice John Roberts, with his hands on a Bible, was sworn in Thursday as the temporary Senate President to oversee the historic impeachment trial of President Donald Trump.

After taking oath Roberts gave the oath of office to 99 of the 100 senators, who will act as jurors.

One was missing because of a family medical problem.

This will only be the third time that a US President is on trial before the Senate after being impeached by the House of Representatives.

Flanked by fellow prosecutors from the House, Adam Schiff, the House Intelligence Committee Chair who led the impeachment investigations against Trump, formally read the charges of obstruction of Congress and abuse of power before the Senate.

Typing in all capital letters, Trump tweeted: "I JUST GOT IMPEACHED FOR MAKING A PERFECT PHONE CALL."

But he may not have to worry beyond the blemish of impeachment to his name as he can expect to be acquitted of the charges because the Democrats will not be able to muster the two-thirds majority needed to convict him and remove him from office.

The two Presidents before him to be tainted by impeachment - Andrew Johnson in 1868 and Bill Clinton in 1998 - were acquitted.

The trial will be a television spectacle that could last about a month and the Democrats hope it will convince some of Trump's supporters to turn against him at the polls in November.

The call Trump was referring to is at the heart of the charges against him. It was made last July to the newly-elected Ukraine President Volodymyr Zelensky and during the call he asked him as a "favour" to investigate the dealings of the former Vice President Joe Biden and his son, Hunter in that country.

Democrats accuse Trump of abusing his powers by asking Zelensky to investigate Joe Biden, the party's front-runner for the nomination to challenge him in the November 3 presidential election, which would amount to inviting foreign interference in US polls.

He is also accused of withholding about $400 million in military aid to Ukraine in a bid to force Zelentsky to launch the investigation.

In the end, the aid was released and there was no Ukrainian probe of the Bidens.

Indo-Asian News Service