Biden remembered those who were killed and called for unity going forward.
Former President Donald Trump's historic second impeachment trial ended with a 57-43 vote to acquit in the Senate. He faced a single charge of incitement of insurrection over his actions leading up to the Jan. 6 riot at the U.S. Capitol.
Trump will be the first president to undergo an impeachment trial after leaving office, but opponents of the impeachment say a trial may be unconstitutional.
2nd Impeachment Trial: What this could mean for Trump
The public should expect to see four attorneys on the Trump team during the trial: David Schoen, Bruce Castor, Michael van der Veen and Julieanne Bateman.
The newly appointed legal team submitted its first legal brief on Feb. 2, arguing the trial is unconstitutional because Trump is no longer in office. The trial's legality has been called into question since the beginning but the Senate voted to proceed.
The brief also argues that Trump's use of social media and comments made on Jan. 6 are protected by the First Amendment. There is a possibility that Trump's defense may skirt into claims of election fraud, despite Trump and his allies losing dozens of court cases on the issue and the 2020 election results being certified by Congress.
Trump's lawyers filed another brief on Feb. 8, further elaborating their argument against the trial's constitutionality and asking the Senate to dismiss the charges. House impeachment managers followed with a five-page response to Trump's legal team.
-ABC News' Katherine Faulders and Tia Humphries
Democrats are preparing to argue that Trump constituted the "most grievous constitutional crime ever committed by a president" and is "singularly responsible" for the deadly riot at the Capitol on Jan. 6, and that the Senate can't establish "a January exception to the Constitution," according to senior aides on the impeachment managers' team.
The managers, led by Rep. Jamie Raskin, D-Md., have been meeting every day -- sometimes twice a day -- since they were named to work on the case, mostly virtually given the pandemic.
They promised a "succinct and to the point and non-repetitive" argument laying out how the attack happened in "plain sight" and left behind "overwhelming evidence."
"This is not about politics," the aides said, adding that they won't touch any senators' support of Trump.
"This is personal for them. They experienced the attack, their staff experienced the attack," one aide said. "They're not taking this lightly, they find no joy in this."
On the constitutional question of trying a former president, aides said, "This will not be like a constitutional convention," and likened it instead to a "violent criminal prosecution."
They called the argument that the trial is unconstitutional "just not common sense."
"It is unthinkable that the framers would say that that a president could not be impeached, no matter what he or she did in the final days of office would allow the president to misuse power at the most dangerous time right when a president wants to hold on to power, that the president can do whatever that president wants without fear of losing office or be barred from running again. That cannot be," one aide said.
-ABC News Congressional Corespondent Rachel Scott, Katherine Faulders, Benjamin Siegel, Trish Turner and Allison Pecorin
It's the trial most of Washington can't wait to be on the other side of -- and where the final vote is already almost beside the point.
The case against former President Donald Trump will be made to senators and voters simultaneously, of course. Either set of jurors were also witnesses in a certain way; the videos and social-media posts that became famous a month ago will be key to the case House managers make, in the very Senate chamber that was desecrated by rioters.
Trump's defense hinges on the argument that he deserves no blame for the attack. In the brief his lawyers submitted to the Senate, they claim that his "metaphorical 'fighting' language" does not link him to the actions of a "small group of criminals."
But as the new investigation launched Monday by Georgia's secretary of state makes clear, it's not just Trump's words at the rally on Jan. 6 that are alleged to have contributed to attempts to block Congress and former Vice President Mike Pence from doing their jobs.
Plenty of those who stormed the Capitol cited Trump's direct words. Even more were responding to what the now-former president was both saying or doing in the fateful weeks after he lost the election but refused to admit it.
Trump's lawyers are calling the impeachment trial "political theater." Trump put on his own show first -- and the strongest argument his legal team may have is that he should have been taken neither seriously nor literally.
-ABC News Political Director Rick Klein
