In making their arguments, Mr. Trump’s lawyers also revealed new details about the investigation. They took on Mr. Comey’s account of Mr. Trump asking him privately to end the investigation into Mr. Flynn. Investigators are examining that request as possible obstruction.
But Mr. Trump could not have intentionally impeded the F.B.I.’s investigation, the lawyers wrote, because he did not know Mr. Flynn was under investigation when he spoke to Mr. Comey. Mr. Flynn, they said, twice told senior White House officials in the days before he was fired in February 2017 that he was not under F.B.I. scrutiny.
“There could not possibly have been intent to obstruct an ‘investigation’ that had been neither confirmed nor denied to White House counsel,” the president’s lawyers wrote.
Moreover, F.B.I. investigations do not qualify as the sort of “proceeding” an obstruction-of-justice statute covers, they argued.
“Of course, the president of the United States is not above the law, but just as obvious and equally as true is the fact that the president should not be subjected to strained readings and forced applications of clearly irrelevant statutes,” Mr. Dowd and Mr. Sekulow wrote.
But the lawyers based those arguments on an outdated statute, without mentioning that Congress passed a broader law in 2002 that makes it a crime to obstruct proceedings that have not yet started.
Samuel W. Buell, a Duke Law School professor and white-collar criminal law specialist who was a lead prosecutor for the Justice Department’s Enron task force, said the real issue was whether Mr. Trump obstructed a potential grand jury investigation or trial — which do count as proceedings — even if the F.B.I. investigation had not yet developed into one of those. He called it inexplicable why the president’s legal team was making arguments that were focused on the wrong obstruction-of-justice statute.