A senior Democratic congressman sued former president Donald Trump Tuesday, accusing him of violating the 19th century "Ku Klux Klan Act" by supporting the January 6 attack on the US Capitol.
Bennie Thompson accused Mr Trump, his lawyer Rudy Giuliani, and extremist groups the Proud Boys and Oath Keepers of violating the 1871 act by supporting efforts to stop Congress from certifying Joe Biden as the new US president.
Mr Thompson, who is Black and the chairman of the House Homeland Security Committee, cited a law originally created to protect the rights of African Americans after the Civil War and the end of slavery.
The lawsuit was filed in federal court in Washington two days after Mr Trump was acquitted of supporting insurrection in an impeachment trial in the Senate.
While a majority of the Senate, 57 of the 100 members, voted for conviction, it fell short of the two-thirds majority required.
The act was designed to give the US president powers to oppose violently racist groups like the Ku Klux Klan which sprung up in the wake of the 1861-65 Civil War to oppose equal rights for Black Americans.
One seldom-invoked clause of the act, 1875, forbids conspiracy to obstruct federal officeholders from performing their jobs.
Mr Thompson alleged that Mr Trump, Mr Giuliani and the two groups conspired "by force, intimidation and threats" to prevent him from discharging his official duty to carry out the certification of Mr Biden's election win.
"The defendants acted in concert to incite and then carry out a riot at the Capitol by promoting an assembly of persons to engage in tumultuous and violent conduct or the threat of it that created grave danger of harm to the Plaintiff and to other Members of Congress," he said.
Civil rights organisation the National Association for the Advancement of Coloured People (NAACP) is representing Mr Thompson in the suit.
He said the attack on the Capitol, which temporarily halted the certification, left five people dead and scores injured, arose from a "common plan that the Defendants pursued since the election held in November 2020".
It culminated in the 6 January White House rally attended by members of the two groups, in which both Mr Trump and Mr Giuliani directly urged them to halt the certification.
Thompson is seeking unspecified compensatory damages for "emotional distress" due to the attack, and punitive damages to punish Mr Trump and the other defendants for "unlawful conduct".
