Washington ? National Intelligence Director Dennis Blair is resigning under pressure from the White House, ending a tumultuous 16-month tenure marked by intelligence failures and spy agency turf wars.

Blair, a retired Navy admiral, is the third director of national intelligence, a position created in response to public outrage over the failure to prevent the Sept. 11, 2001, terrorist attacks.

His departure underscores the disorganization inside the Obama administration’s intelligence apparatus, rocked over the past six months by a spate of high-profile attempted terror attacks that revealed new national security lapses. And it comes two days after a stark Senate report criticized Blair’s office and other intelligence agencies for new failings that, despite a top-to-bottom overhaul of the U.S. intelligence apparatus after 9/11, allowed a would-be bomber to board a Detroit-bound airliner on Christmas Day.