When Darrell Issa called Jay Carney a "paid liar" this week, his critics figured he'd finally gone too far—that his one-step-ahead-of-the-facts rhetoric would force Republicans to rein him in. They figured wrong. For all the polite Washington handwringing over that single comment, the truth is this: Issa’s aggressive approach is just what the Republican House leadership wants. House Majority Leader Eric Cantor singled out Issa for praise at a closed-door GOP conference meeting on Tuesday. Hours later, Cantor gave him plaudits on national television, saying on CNN that Issa and other GOP chairmen investigating the IRS were doing “a fantastic...