Despite his acquittal by the Senate, former President Trump’s legal problems may not be over.

He’s already been hit with one lawsuit connected to allegations he incited last month’s riot at the U.S. Capitol and faces the possibility of more to come.

Shortly after the Senate voted against convicting Trump in his impeachment trial Saturday, Senate Minority Leader Mitch McConnell (R-Ky.) argued that impeachment was not the proper venue for holding the former president accountable and suggested he could face legal consequences for his actions.

McConnell, who voted to acquit, said Trump is “practically and morally responsible” for provoking the riot.

"President Trump is still liable for everything he did while he was in office, as an ordinary citizen, unless the statute of limitations has run. ... [He] didn't get away with anything yet," McConnell said in a floor speech.

Three days later, the NAACP filed a lawsuit on behalf of Rep. Bennie Thompson (D-Miss.) against Trump, his adviser Rudy Giuliani and right-wing groups for inciting the mob that overran the Capitol on Jan. 6, disrupted the counting of Electoral College votes by Congress and left five people dead.

The lawsuit alleges that Trump violated a Reconstruction-era law known as the Ku Klux Klan Act, which forbids conspiring to "prevent, by force, intimidation, or threat," public officials from carrying out their duties.

“You cannot move forward if you don't address the illegality of what took place, the treasonous act,” NAACP President Derrick Johnson told The Hill on Tuesday. “If you try to move forward without holding people accountable, you only set yourself up [for] future activity that could possibly be successful in toppling our democracy."

The allegations echo those brought by the House impeachment managers: that in the weeks after the election and in the hours before the riot, Trump incited his supporters with outlandish claims that electoral fraud caused his defeat.

In response to the lawsuit, Jason Miller, a spokesman for Trump, maintained that the former president was not responsible for what happened on Jan. 6.

“President Trump has been acquitted in the Democrats’ latest Impeachment Witch Hunt, and the facts are irrefutable. President Trump did not plan, produce or organize the Jan. 6th rally on the Ellipse," Miller said in a statement. "President Trump did not incite or conspire to incite any violence at the Capitol on Jan. 6th. Speaker Nancy Pelosi and Washington, D.C., Mayor Muriel Bowser must answer questions as to why they rejected additional security and National Guard assistance in the run-up to Jan. 6th."

Miller did not immediately respond when asked for comment on the possibility that Trump could face more cases over the Capitol riot.

Gregory Magarian, a constitutional law professor at the Washington University School of Law, said Trump could very well win against any of the civil suits that might be brought against him, but that he should be concerned about the possibility of spending his time following the presidency swamped in litigation.

"These are not frivolous cases," Magarian said. "There is a realistic possibility that Trump could end up facing legal liability. As with anything else, if you're trying to succeed with something you diversify your efforts. I think we're probably going to see a variety of different kinds of lawsuits based on a variety of different egregious, things that Trump did."

"These lawsuits are going to be brought under different legal theories," he continued. "They're going to be brought in different courts in different jurisdictions. If you're Trump, your concern is OK, am I going to skate on all of this stuff? It only takes, you know, potentially one or two big successes for the plaintiffs to really cause him some problems."

Some of Trump's critics have also called for him to be charged criminally for provoking his supporters to commit violence. It's unclear whether the Biden administration would take the unprecedented step of prosecuting a former president, but the possibility adds to the criminal liability that Trump faces elsewhere, including investigations into his business practices in New York and a district attorney's probe into a call he made pressuring Georgia Secretary of State Brad Raffensperger (R) over the state's election results.

Chuck Rosenberg, a former U.S. attorney and senior FBI official, says that it would be difficult for prosecutors to secure a conviction against Trump based on the evidence he's seen.

"I think Sen. McConnell's characterization is correct — that Trump is morally responsible — but you need more evidence to hold him criminally responsible," Rosenberg said. "The question is, do you have a good-faith basis — sufficient predication — to open a criminal investigation? Absolutely. It's not a close call."

Rosenberg says that prosecutors would need to establish Trump's intent in rallying his supporters to protest what he had convinced them was a stolen election.

"Unless he kept all of his thoughts to himself, which seems unlikely for Mr. Trump, I'd want to talk to everyone he talked to," Rosenberg said. "What did he tell them? When did he tell it to them?"

As for the potential civil lawsuits like the one already filed by Thompson and the NAACP, Magarian said that Trump’s lawyers will likely argue that comments he made while in office are at least partially protected from legal liability, forcing federal judges to grapple with whether they can impose restraints on an elected official’s speech.

“I think that kind of big picture tension, which comes up all the time in constitutional cases of various kinds, is going to be very prominent in these Trump lawsuits,” Magarian said.