President Donald Trump's legal team defended his claim to absolute immunity from criminal investigation and insisted on a federal forum to decide on his challenge to a Manhattan grand jury subpoena seeking his tax returns in a brief filed in the U.S. Court of Appeals for the Second Circuit at 4:30 p.m. Friday.

"There has been broad bipartisan agreement, for decades if not centuries, that a sitting President cannot be subjected to criminal process," Trump's lawyers wrote, continuing their argument that a Manhattan grand jury should not be able to subpoena Trump's accounting firm, Mazars USA, for his tax returns.

Trump sued Manhattan District Attorney Cyrus Vance Jr. in the Southern District of New York in September, arguing that presidents should not be subject to investigation or indictment by local prosecutors. The grand jury had subpoenaed Trump's accounting firm for eight years of his tax returns in August.

U.S. Senior District Judge Victor Marrero of the Southern District of New York dismissed the case Monday, citing the 1971 U.S. Supreme Court decision Younger v. Harris as he ruled that federal courts should not intervene in this kind of state case. Trump immediately appealed to the Second Circuit, which agreed to hear the case and stayed enforcement of the subpoena until arguments have been made.

Anticipating the appeal, Marrero laid out his reasoning on the merits of Trump's presidential immunity argument, finding that a court with appropriate jurisdiction should also dismiss the case. Marrero wrote that the writers of the U.S. Constitution carefully avoided giving presidents the all-encompassing immunity of British kings.

He also criticized the authority Trump's legal team has given to memos from the U.S. Department of Justice's Office of Legal Counsel. The memos may hold that presidents are immune from criminal investigation and prosecution, Marrero wrote, but they do not have the legal weight of court rulings.

The weight of the memos is becoming increasingly relevant in New York and in Washington, where Chief U.S. District Judge Beryl Howell for the District of Columbia raised questions about them Tuesday. The memos are binding for federal prosecutors, as the National Law Journal reported, but state prosecutors and Congress potentially have more flexibility.

Trump's attorneys said local criminal investigation of a president is "unimaginable."

"That the Constitution empowers thousands of state and local prosecutors to embroil the President in criminal proceedings is unimaginable," they wrote in a brief signed by William Consovoy of Consovoy McCarthy.

Another subpoena for Trump's tax returns, from Democrats in the U.S. House of Representatives, cleared a hurdle in the U.S. Court of Appeals for the D.C. Circuit on Friday, when a panel of judges ruled 2-1 that revealing Trump's tax returns would not create an undue burden for him or prevent him from doing his job as president.

In an amicus brief filed Friday afternoon, U.S. Department of Justice lawyers argued that Marrero fundamentally misunderstood the relationship between a president and state criminal processes.

Asserting any state criminal jurisdiction over the president raises constitutional issues, according to the amicus brief, which was signed by Justice Department lawyer Gerard Sinzdak of Main Justice's Civil Division Appellate Staff. The grand jury subpoena will burden the president so much that it could interfere with his ability to perform his constitutional duties, Sinzdak wrote.

"Just as an indictment and prosecution could be expected to divert the President's attention and energy from his official duties to his personal legal jeopardy, a demand for the President's own records will necessarily be a distraction when the President himself is a possible focus of the criminal investigation," Sinzdak wrote.

Vance's brief is due at 5 p.m. Tuesday, and Trump's reply brief is due Thursday. Arguments before a panel of judges are scheduled for Oct. 23.

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