Geoffrey S. Berman, who headed the Manhattan office, says in a book the Justice Department pushed cases, against John Kerry and others, to help Mr. Trump.
As the department decides whether to appeal the ruling on a special master, it is balancing a desire to speedily resolve the inquiry with the need to limit an expansive view of executive power.
Judge Aileen M. Cannon has issued the first highly scrutinized ruling of her short judicial career, involving the person who put her on the bench: former President Donald J. Trump.
The former attorney general, who chose not to indict Mr. Trump in the Russia inquiry, said the Justice Department was justified in investigating his handling of government materials.