Democrats said they looked to the courts for possible civil and criminal charges against the former Republican president over the assault by his supporters on Jan. 6, which left five people dead.
The Senate trial concluded on Saturday with a 57-43 vote in favor of convicting Trump, falling short of the two-thirds majority needed to do so.
Of the seven Republicans who joined the Senate's 48 Democrats and two independents in voting to convict, some faced swift backlash in their home states.
Senator Bill Cassidy said on Sunday he believed more of his constituents would come to agree with his vote over time as the facts became known. Republican party leaders in Cassidy's home state of Louisiana voted on Saturday to censure him.
"I have the privilege of having the facts before me. As these facts become more and more out there ... and folks have a chance to look themselves, more folks will move to where I was," Cassidy told ABC's "This Week" when asked about the censure.
"I'm attempting to hold President Trump accountable ... I am very confident as time passes, people will move to that position," Cassidy said.
The party leader in Pennsylvania also criticized its Republican Senator Pat Toomey for voting to convict.
"The vote to acquit was the constitutionally correct outcome," Pennsylvania Republican Chairman Lawrence Tabas said in a statement on Saturday.
Cassidy declined to say whether Trump should face criminal charges. But Democratic Senator Chris Coons told ABC he thought this could happen.
"I think there's ground for further proceedings, both civil and criminal, against former President Trump," Coons said.
Coons said the country needed to set up a 9/11-style commission to investigate the events of Jan. 6. But he believed the Senate trial "reached its natural conclusion" on Saturday.
UNITY
The assault on the Capitol forced lawmakers to evacuate congressional chambers in fear for their safety in the middle certifying Biden's win in the November election, which Trump falsely maintained he lost due to widespread electoral fraud.
Biden, who took office on Jan. 20, appealed for unity to "heal this uncivil war and heal the very soul of our nation," saying each American had a duty and a responsibility to defend the truth.
"This sad chapter in our history has reminded us that democracy is fragile. That it must always be defended. That we must be ever vigilant. That violence and extremism has no place in America," Biden said in a statement. "That is the task ahead. And it's a task we must undertake together. As the United States of America."
Trump, while hailing the acquittal, called the House impeachment and trial in the Senate a "witch hunt." Trump is the only president in U.S. history to be impeached twice.
Democratic Speaker of the House of Representatives Nancy Pelosi called Republicans who did not support conviction "cowardly."
Biden, who stayed largely out of the fray during the impeachment proceedings, is eager to pass a $1.9 trillion pandemic relief bill and have the remaining nominees for his Cabinet confirmed by the Senate. But lawmakers' disagreements are likely to linger.
The Republican Senators who voted in favor of conviction also included Richard Burr, Susan Collins, Lisa Murkowski, Mitt Romney, and Ben Sasse.
Murkowski, of Alaska, is the only one of the seven up for re-election in 2022. The other six either are retiring from Congress or their six-year terms do not expire that year.
"I'm sure that there are many Alaskans that are very dissatisfied with my vote, but I'm sure there are many Alaskans that are proud of my vote," Murkowski told Politico after the trial.
Trump has repeatedly threatened to go after Republicans who do not support him by endorsing opponents in their primary elections. On Saturday he indicated he was thinking about his own political future, without divulging details.
