Obama has already demonstrated an extraordinary ability to change the limits of what one can say publicly. His greatest achievement up to now is that, in his refined non-provocative way, he has introduced into public speech topics which had hitherto been de facto unsayable: the continuing importance of race in politics, the positive role of atheists in public life, the necessity to talk with "enemies" like Iran or Hamas, and so on. This is just what US politics needs today more than anything, if it is to break out of its gridlock: new words which will change the way we think and act.