Lawyers for former President Donald J. Trump launched a flurry of attacks on Thursday night against the federal charges accusing him of illegally holding on to classified documents after he left office, filing more than 70 pages of court papers seeking to have the case thrown out.

In four separate motions to dismiss the case, Mr. Trump’s lawyers made a barrage of legal arguments in seeking to circumvent a criminal case that many legal experts consider the most ironclad of the four against him. They attacked the law he is accused of violating, questioned the legality of the special counsel prosecuting him and argued that he is shielded from prosecution by presidential immunity.

Some of the arguments tested the boundaries of credulity and flew in the face of prior court rulings. Many appeared designed to delay the case from moving toward trial, a strategy that Mr. Trump has pursued in all of the criminal proceedings he is facing.

In one of their most brazen motions, Mr. Trump’s lawyers claimed that he was immune from prosecution on the classified documents charges even though a federal appeals court roundly rejected that argument this month when he sought to use it in a separate case, in which he stands accused of plotting to overturn the 2020 election.

Mr. Trump’s claims of immunity have always rested on the theory that he could not be charged for any actions he undertook as president. And his lawyers sought to argue in their motion that he should not be prosecuted for moving dozens of classified records from the White House to Mar-a-Lago, his private club and residence in Florida, because his initial decision to do so was made while he was in power.

But that line of reasoning seemed largely intended to get around the text of the law — the Espionage Act — that prosecutors have accused him of violating. Mr. Trump has been charged specifically with willfully retaining the classified documents, and prosecutors say that his purposeful retention of the records continued for many months after he left office, ending only in August 2022 when F.B.I. agents, executing a search warrant, seized them at Mar-a-Lago.