The nomination of attorney general hopeful Michael Mukasey is in further doubt today after he refused Democratic calls to acknowledge that waterboarding is a form of torture. In a letter to Senate Democrats, Mukasey said he finds waterboarding “repugnant” but maintained he doesn’t know if it violates U.S. laws against torture. Several Senate Democrats have vowed to hinge their confirmation vote on Mukasey’s waterboarding stance. On Tuesday, three Democratic senators — all presidential candidates — Hillary Rodham Clinton, Barack Obama and Joe Biden — said they would oppose Mukasey’s nomination.