A year after the House of Representatives impeached him for the first time, former US President Donald Trump finds himself at the center of an unprecedented second impeachment trial that begins Tuesday in the US Senate. 

The trial focuses on the chaos of Jan. 6, when hundreds of Trump supporters stormed the headquarters of Congress and clashed with the police, trying to prevent a formal session to validate Joe Biden's election victory.

Many consider the events as the most dangerous attack on American democracy since the Civil War in the 1860s.

Jan. 13, the House of Representatives charged him with "inciting insurrection," making Trump the only US president to be sacked twice.

Through the trial, the Democrats aim to ban Trump from holding any federal office in the future, if they manage to achieve the goal of his conviction.

Trump's opponents say he played a role in the attack by violating his oath and inciting supporters.

But the Republican billionaire and his allies insist that the trial itself is unconstitutional, as the Senate can convict a sitting president and remove him from power, but it cannot do so against a private citizen.

House of Representatives Speaker Nancy Pelosi, who formed a team of nine Democrats to administer the impeachment procedures and indict Trump, insisted on the need for a trial, believing that failure to convict him would harm US democracy.

"We'll see if the Senate will be a council of courage or cowardice," she told reporters Thursday.

- 'Explosive barrel' -

Conviction of Trump would require the votes of more than two-thirds of the senators, which means that 17 Republicans will have to defect from the rest of the party and join all 50 Democrats, in a scenario that seems unlikely.

But while Trump still maintains strong support from his electoral base, the attack may have lowered his popularity, which is not in the interest of the 74-year-old former president, who liked the idea of running again for the presidency in 2024.

And the Democrats who run the impeachment process aren't only intending to stick to legal theories during the session. A memo summarizing their arguments reveals the tone they would use, as they accused Trump of "preparing a barrel of explosives, lighting a match, and then seeking personal benefit from the chaos that followed."

They also indicated their intention to use many of Trump's public statements against him, including the speech he made on January 6, prior to the attack, to a crowd of his supporters near the White House, where he called on them to "show their strength."

At the time, Trump said, "You will never take our country back if you are weak," calling on them to "fight fiercely."

Media reports indicate that the Democrats are not considering issuing a subpoena to force him to attend.

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