On the defensive over the economy and health care, the White House is shooting back with a double-barreled message for its critics and skeptics. To Republicans who say the stimulus isn’t working: Back off. To moderate Democrats wary of health care reform: We’re watching you. Earlier this week, the administration launched a coordinated effort to jam Senate Minority Whip Jon Kyl, an Arizona Republican who’s argued that the government should “cancel the rest of the stimulus spending.” No fewer than four Cabinet secretaries wrote to Arizona Gov. Jan Brewer — also a Republican — to ask her if she agreed...