Everyone elected president comes into office modeling himself on some predecessor: Abraham Lincoln, Franklin Roosevelt, Ronald Reagan. But those who win re-election eventually end up wondering whether they should have emulated James K. Polk instead. Why? Because he promised to serve only one term, and he stuck to it. As Steve Chapman observes, Barack Obama is probably reaching that stage about now. Ten months after concluding a victorious campaign, he finds himself with a public approval rating of 44 percent. That's down 10 points since December—and the same as that of George W. Bush at this point in his presidency.