The indictment of John Bolton on charges of sharing classified information is stronger than the recent charges against two other political foes of President Donald Trump, but the former U.S. national security adviser has several options for mounting a defense, legal experts said.

Bolton, 76, said in a statement on Thursday that he was the latest target in Trump's weaponization of the Justice Department against his enemies. He pleaded not guilty on Friday to 18 counts of transmitting and retaining national defense information.

Trump, a Republican who campaigned for the presidency on a vow of retribution after facing multiple legal woes following his first term in the White House that ended in 2021, has dispensed with decades-long norms designed to insulate federal law enforcement from political pressures.