This week Evan Bayh, a senator from Indiana who nearly became Barack Obama’s vice-president, said he was retiring from the Senate, blaming the inability of Congress to get things done. Cynics think Mr Bayh was also worried about being beaten in November (though he was ahead in the polls). Yet the idea that America’s democracy is broken, unable to fix the country’s problems and condemned to impotent partisan warfare, has gained a lot of support lately (see article).

Certainly the system looks dysfunctional. Although a Democratic president is in the White House and Democrats control both House and Senate, Mr Obama has been unable to enact health-care reform, a Democratic...