He added: “This is me, and hopefully others, having our day in court to address the atrocities of Jan. 6. I trust the better judgment of the courts because obviously Republican members of the Senate could not do what the evidence overwhelmingly presented.”
Mr. Thompson said he had already received a second dose of a Covid vaccine by Jan. 6 and therefore did not quarantine after his close contacts with colleagues who tested positive. But he noted, “There were a number of members who were very concerned about being housed in those numbers with people refusing to wear masks.”
Both Democratic and Republican members of Congress have recently raised the prospect of Mr. Trump being held accountable in the courts for the riot. Senator Mitch McConnell, the Republican leader, voted to acquit Mr. Trump in the impeachment trial but then appeared to encourage people to take their fight to the courts.
“He didn’t get away with anything, yet,” Mr. McConnell said at the trial’s conclusion, noting: “We have a criminal justice system in this country. We have civil litigation.”
Derrick Johnson, president of the N.A.A.C.P., said the decision to seek compensatory and punitive damages was rooted in a history of tools that have worked to fight back against white supremacy.
“The Southern Poverty Law Center filed a lawsuit against the Ku Klux Klan that bankrupted a chapter,” he said, referring to a 2008 judgment against a Kentucky-based Klan outfit that ordered the group to pay $2.5 million in damages. “This is very similar. If we do nothing, we can be ensured these groups will continue to spread and grow in their boldness. We must curb the spread of white supremacy.”
While much of the focus of the impeachment trial rested on how the violent mob was threatening former Vice President Mike Pence as well as congressional leaders like the House speaker, Nancy Pelosi, N.A.A.C.P. officials said the attack was deeply rooted in racial injustice.