Democratic prosecutors making the case that Donald Trump incited a deadly insurrection by encouraging his supporters to march on the US Capitol have warned the Senate that if it fails to convict the former president, "he can do this again".
The first three days of Trump's impeachment trial focused on his fiery words to supporters in the weeks leading up to the January 6 attack, when he falsely claimed that his election defeat by Democrat Joe Biden was the result of fraud and that the crowd needed to "fight" and "stop the steal".
The Democrats appear highly unlikely to secure a conviction and bar Trump from holding public office again given only six Republicans voted with Democrats in the 100-seat chamber to proceed with the trial.
"If he gets back into office and it happens again, we'll have no one to blame but ourselves," lead impeachment manager Representative Jamie Raskin told the Senate on Thursday, wrapping up the prosecution arguments.
Fellow Democratic Representative Ted Lieu told the senators he worries about what would happen if Trump runs in 2024 and loses.
"I'm not afraid of Donald Trump running again in four years. I'm afraid he's going to run again and lose, because he can do this again," Lieu said.
The Democratic prosecutors provided example after example of Trump's actions beforer the rampage to illustrate what he intended when he told supporters to go to the Capitol and "fight like hell" as Congress convened to certify Biden's election victory.
"January 6 was not some unexpected radical break from his normal law-abiding and peaceful disposition. ... This was his essential MO," Raskin said.
"He knew that egged on by his tweets, his lies and his promise of a 'wild' time in Washington to guarantee his grip on power, his most extreme followers would show up bright and early, ready to attack, ready to engage in violence, ready to 'fight like hell' for their hero."
The Democratic-led House on January 13 charged Trump with inciting an insurrection. His term ended on January 20.
A two-thirds majority in the Senate would be needed to convict, which means at least 17 Republican senators would have to defy Trump, who remains popular with most Republican voters and has shown interest in running for president again in 2024.
Dozens of former Republican officials who said they are frustrated with their party's unwillingness to stand up to Trump are in talks to form a centre-right breakaway party, four people involved in the discussions told Reuters.
The nine House impeachment managers have argued that Trump planted the seeds for the riot by encouraging violence and making false claims about widespread electoral fraud long before January 6, and must be held accountable for what happened.
Five people including a police officer died in the riot. Two more police officers involved in the response died by suicide in the days afterward.
Although the prosecutors' arguments were generally praised by both parties, some Republican senators said they were still not convinced.
Senator James Lankford told reporters the managers failed to connect the dots between Trump and the rioters.
Senator James Inhofe said: "It's just redundant, the same thing over and over again. ... To me, the more you hear it, the less credibility there is in it."
Looking ahead to Trump's defence, the House managers disagreed that his incendiary language was protected by the constitutional right to free speech.
The trial is expected to finish at the weekend.
Trump is the first US president to be impeached twice and the first to face trial after leaving office. His first impeachment trial, which stemmed from his efforts to pressure Ukraine to investigate Biden, ended in an acquittal a year ago in what was then a Republican-controlled Senate.