A U.S. congressional committee probing the Jan. 6, 2021, assault on the U.S. Capitol has sought to build a case that then-President Donald Trump behaved illegally when he tried to overturn his 2020 electoral defeat, but what charges could prosecutors bring against Trump and how might he defend himself?

Here are some ideas being floated:

OBSTRUCTING AN OFFICIAL PROCEEDING

In a March 2 court filing, the committee detailed Trump's efforts to persuade then-Vice President Mike Pence either to reject slates of electors for Joe Biden, who won the election, or delay a congressional count of those votes.

The president's efforts likely violated a federal law making it illegal to "corruptly" obstruct any official proceeding, or attempt to do so, said David Carter, the California federal judge overseeing the case said in a March 28 written order.

At a primetime hearing on Thursday, committee members alleged that Trump watched the violence at the U.S. Capitol unfold live on television and failed to prevent it. Witnesses testified as to Trump's reluctance to tell the rioters to leave for hours after they breached the building.

Jennifer Rodgers, a former federal prosecutor and lecturer at Columbia Law School, said a prosecutor would include that testimony if they were to try Trump on an obstruction charge because it would show his intent at the time.

"(Trump) was urged by everyone around him to act, to try to do something to stop it, and he chose not to," Rodgers said.

CONSPIRACY TO DEFRAUD THE UNITED STATES

In the March 2 filing, the committee said it was likely that Trump and others conspired to defraud the United States, which criminalizes any effort by two or more people to interfere with governmental functions "by deceit, craft or trickery."

In addition to Trump's efforts to pressure Pence, the committee cited his attempts to convince state election officials, the public and members of Congress that the 2020 election was stolen, even though several of his allies told him there was no evidence of fraud.

Cassidy Hutchinson, an aide to then-White House Chief of Staff Mark Meadows, previously testified that Trump was so enraged by then-Attorney General Bill Barr's interview with the Associated Press saying there was no evidence of election fraud that Trump threw his lunch at the wall, breaking a porcelain dish and leaving ketchup dripping down the wall.

SEDITIOUS CONSPIRACY?

Prosecutors have already charged more than a dozen members of the far-right Proud Boys and Oath Keepers groups who were at the Jan. 6 riot with seditious conspiracy, a rarely used statute that makes it illegal to overthrow the U.S. government by force.

To prove Trump committed seditious conspiracy, prosecutors would need to show he conspired with others to use force.

Rodgers said a prosecutor could use Trump's failure to act to bolster such a charge, including testimony that he knew he was the only person who could get the rioters to leave the Capitol.

TRUMP'S DEFENSE?

Trump has repeatedly denied doing anything illegal in connection with the Jan. 6 events.

In a series of posts on his social media platform Truth Social on Thursday, Trump attacked the House panel, but maintained his false claims that the 2020 election was stolen. "So many lies and misrepresentations by the corrupt and highly partisan Unselect Committee!" he wrote.

If the Justice Department were to bring charges, prosecutors' main challenge would be to prove that Trump acted with corrupt intent, experts said.

Trump could argue he sincerely believed that he won the election and that his well-documented efforts to pressure Pence and state election officials were not meant to obstruct Congress or defraud the United States, but to protect the election's integrity.

DOES THIS MEAN TRUMP WILL BE CRIMINALLY CHARGED?

No. Neither Carter nor the committee can charge Trump with federal crimes. That decision would have to be made by the Justice Department, led by Attorney General Merrick Garland.

The department is conducting its own investigation of the Jan. 6 events. Any decision to indict Trump would have enormous political consequences as the former president weighs another run for the White House in 2024. The department did not respond to a request for comment.