Conservatives who argue against the repeal of “Don’t Ask, Don’t Tell” will have to do so without the support of one of their heroes: General David Petraeus told Congress on Tuesday that “I believe the time has come to consider a change to ‘Don’t Ask, Don’t Tell.” He stressed that it should be done “in a thoughtful and deliberative manner.” In recent weeks, Petraeus had refused to give an opinion on the policy.