The second impeachment trial of Donald Trump started Tuesday in the Senate, with the former U.S. president facing a charge of inciting a deadly attack on the Capitol last month amid his refusal to concede defeat in his bid for re-election.

The Democrats are hoping that the Senate will convict the still-influential 74-year-old Republican and disqualify him from running for the presidency again. But the chances of his conviction, which would require a two-thirds vote, appear slim in the evenly divided chamber.

U.S. President Donald Trump speaks at "Save America March" rally in Washington, United States on Jan. 6, 2021. (Anadolu Agency/Getty/Kyodo)

With no witnesses likely to be called to testify, the trial is expected to end relatively quickly.

The first day culminated in a vote on the constitutionality of an impeachment trial of a former president, which has no precedent. A majority -- all 50 Democrats and six Republicans -- acknowledged that the Senate has such jurisdiction.

Trump was impeached by the Democratic-led House of Representatives just before the end of his presidency on Jan. 20 on a charge of incitement of insurrection. He became the first president in U.S. history to be handed the rebuke twice.

Showing video footage of a pro-Trump mob storming the Capitol on Jan. 6, apparently emboldened by the then president's urging during a rally held shortly before the attack, Jamie Raskin, one of the House Democrats serving in the role of prosecutor, said their case is based on "cold, hard facts."

As intruders violently clashed with police, smashed windows and ransacked offices, Congress members had to take shelter, halting a process to certify Democrat Joe Biden's win in the November presidential election. Five people died in the riot, including a police officer and a fervent Trump supporter who was shot by police.

Raskin, who emotionally recalled the horrifying moments he and family members who were with him went through during the Jan. 6 rampage, said no impunity should be offered for conduct in the last few weeks of a president's time in office before the Jan. 20 swearing-in of a successor.

"We cannot have presidents inciting and mobilizing mob violence against our government and our institutions because they refuse to accept the will of the people under the Constitution of the United States," he said.

Pro-Trump supporters storm the U.S. Capitol following a rally with President Donald Trump on Jan. 6, 2021 in Washington, D.C. Trump supporters gather in the nation's capital to protest the ratification of President-elect Joe Biden's Electoral College victory over President Trump in the 2020 election. (Getty/Kyodo)

One of Trump's lawyers, David Schoen, however, argued that an impeachment trial of a private citizen is unconstitutional and pointed to the risks of allowing the Senate to "go back in time and impeach any civil officer who ever served for anything that occurred during the course of their service."

He also argued that the sole goal of the House Democrats in pursuing the conviction is to "use these proceedings to disenfranchise at least 74 million Americans" who voted for Trump in the election, and to ensure that "neither they nor any other American ever again can cast a vote for Donald Trump."

As the trial moves on, Trump's defense counsel is also expected to make the case that the former president did not engage in insurrection or rebellion against the United States.

During the rally on Jan. 6, Trump spoke to thousands of his supporters in Washington, reiterating his baseless claims of widespread election fraud and urging the crowd to march to the Capitol and "fight like hell" or "you're not going to have a country anymore."

Trump's lawyers have said earlier in writing that his speech, taken in its entirety, was "never directed to inciting or producing any imminent lawless action," and the people who criminally breached the Capitol did so "of their own accord."

The lawyers have also said the article of impeachment violates the president's right to free speech guaranteed under the Constitution.

The Democrats, together with two Democratic-leaning independents, hold 50 seats in the Senate and hold a majority because of the tie-breaking vote of Vice President Kamala Harris. They need at least 17 Republicans to come to their side to convict Trump if all 100 senators participate in the vote.

Trump was first impeached in December 2019, charged with abusing the power of his office by pressuring Ukraine to investigate Biden in a bid to boost his own chances of re-election.

He was acquitted in the then Republican-controlled Senate in February last year.

In U.S. history, only two other presidents have been impeached -- Andrew Johnson in 1868 and Bill Clinton in 1998 -- but neither was removed from office as the Senate acquitted them.

In U.S. history, only two other presidents have been impeached -- Andrew Johnson in 1868 and Bill Clinton in 1998 -- but neither was removed from office as the Senate acquitted them.