It's never easy to separate politics from policy, and the past 18 months have only increased the degree of difficulty. The U.S. has been through a historic financial crisis followed by a historic election and a series of historic federal gambles — from bailing out AIG and GM to passing a $787 billion stimulus and a $940 billion health-care reform bill. All that risk has made policy more complicated and politics more fraught ("You lie," "Baby killer"). A Bloomberg national poll in March found that Americans, by an almost 2-to-1 margin, believe the economy has gotten worse rather than better...