Attorney General Eric Holder was just months into the job when he announced plans to prosecute the mastermind of the Sept. 11 attacks in a New York courtroom, rather than through the Guantanamo Bay military commission process.

But the idea ran into political opposition and public safety concerns.

The Obama administration's eventual decision to walk away from it was a defeat for Holder and a reminder of the complex legal fight against terrorism.

Holder took office determined to turn the page from Bush administration policies that authorized harsh interrogation techniques against suspected terrorists.

But he will leave with a mixed record of national security decisions that have drawn their own scrutiny and disappointed those who felt he didn't go far enough to distance the Justice Department from past practices.