Donald Trump's lawyers say Senate has no authority to put him on trial

Former President Donald Trump said on Tuesday that the US Senate has no authority to try him as a private citizen on an impeachment charge that he incited the Capitol riots.

Trump became the first US president in history to be impeached twice when the House of Representatives charged him last month with inciting the mayhem inflicted by his followers when they invaded Congress on January 6.

Trump's defence team said that not only does the Senate lack the authority to put Trump on trial as a private citizen but that the chamber also lacks the jurisdiction to prevent Trump from holding office again.

In a pre-trial brief, the House impeachment managers made their case for the Senate to convict, saying the American people should be protected "against a president who provokes violence to subvert our democracy."

Trump's impeachment was triggered by a speech he delivered to a crowd on the National Mall just before the riot, telling them Joe Biden had stolen the presidential election and that they needed to march on Congress and "fight like hell."

The mob stormed the Capitol, fatally wounded one police officer, wrecked furniture and forced terrified lawmakers and vice president Mike Pence to hide, interrupting a ceremony to put the legal stamp on Biden's victory. 

The nine impeachment managers, all Democrats, argued in their sweeping 77-page document that Trump's speech had whipped the crowd into a "frenzy."

Trump, they said, "is singularly responsible for the violence and destruction" during the riot that left five people dead.

During his January 6 speech, Trump repeated false claims that the election was fraudulent and exhorted supporters to march on the Capitol, telling them to "stop the steal," "show strength" and "fight like hell." The rampage interrupted the formal congressional certification of Democrat Joe Biden's election victory and sent lawmakers into hiding for their own safety.

"The Senate must make clear to him and all who follow that a president who provokes armed violence against the government of the United States in an effort to overturn the results of an election will face trial and judgment," the Democratic managers added.

Trump is just the third president to have been impeached, the first to be impeached twice and the first to face trial after leaving office. Members of the 100-seat Senate will serve as jurors in his trial.

Convicting Trump would require a two-thirds majority, meaning 17 Republicans would need to join the Senate's 50 Democrats in the vote. That presents a daunting hurdle. Last week, 45 of the 50 Republican senators voted in favour of a failed bid to dismiss the impeachment charge as unconstitutional because Trump has left office.

A conviction could lead to a second vote banning Trump from holding public office again.

The Tuesday deadline for briefs in the case came just days after he parted ways with his initial legal team amid a reported dispute over how to respond to the charge. Trump is still making his false claims of a stolen election.

In their brief, the Democratic impeachment managers said the Senate has jurisdiction to try Trump now because the House impeached him while in office for acts he committed as president.

"There is no 'January Exception' to impeachment or any other provision of the Constitution," the managers said. "Presidents do not get a free pass to commit high crimes and misdemeanours near the end of their term."

The brief made no mention of any witnesses the managers planned to call during the trial, though it did cite a phone call Trump placed to Georgia Secretary of State Brad Raffensperger urging him to "find" just enough votes to undo Biden's victory in that state.

Trump's first impeachment trial, on charges of abuse of power and obstructing Congress arising from his request that Ukraine investigates Biden and his son Hunter, ended last year in an acquittal by the then Republican-led Senate.

A group of Republican former officials rebutted the argument that the trial was unconstitutional in an open letter released on Tuesday.

It is "essential to focus the nation on the gravity of what Trump did," the group said in a statement.

The three dozen former officials signing the letter included former Governors Christine Todd Whitman of New Jersey and William Weld of Massachusetts and Carter Phillips, a veteran Washington litigator and assistant solicitor general under former President Ronald Reagan.

"It will be a permanent stain on the history of the Republican Party and the legacy of its members in the US Senate if they fail to find a way to hold a president of their party to account for this unprecedented mayhem at our nation's Capitol," the group wrote.