Members of Congress, police officers and government watchdog groups argued in federal court on Monday that Donald J. Trump was liable for major financial damages for his role in inspiring the Jan. 6 attack on Congress, pressing an array of civil suits against the former president amid mounting frustration that he has faced no penalty for the riot.

Over nearly five hours in the United States District Court for Washington, lawyers laid out their cases against Mr. Trump, contending that he deserved to be held responsible for inflaming a violent mob, despite what are typically wide immunity protections for a president’s speech and actions while in office.

“Mr. Trump dispatched the crowd that he assembled,” said Joseph Sellers, the lawyer for a group of House Democrats, including Representatives Barbara Lee of California, Bonnie Watson Coleman of New Jersey and Hank Johnson of Georgia. “After he saw that they were engaged in breaking into the Capitol, instead of trying to calm them, he retweeted his incendiary remarks from the rally before.”