Lawyers for James B. Comey said the case centered on an issue that had already been investigated and had not led to charges, of a purported leak of national security information to The Times in October 2016.
With new intelligence and the possibility of all sides seeking pretexts for action, the war in Iran is entering a dangerous phase ahead of elections in the United States and Israel.
The U.S. government has ordered diplomats and other federal employees to leave Saudi Arabia. It is also drawing down staff at other missions in the region.