Obama’s approach was politically necessary. On a simple calculus of benefits, his proposal would have failed. Perhaps 32 million Americans will receive insurance coverage — about 10 percent of the population. Other provisions add somewhat to total beneficiaries. Still, for most Americans, the bill won’t do much. It may impose costs: higher taxes, longer waits for appointments.

People backed it because they thought it “the right thing”; it made them feel good about themselves. What they got from the political process are what I call “psychic benefits.” Economic benefits aim to make people richer. Psychic benefits strive to make them feel morally upright and superior. But this emphasis often obscures practical realities and qualifications. For example: The uninsured already receive substantial medical care, and it’s unclear how much insurance will improve their health.

Purging moral questions from politics is both impossible and undesirable. But today’s tendency to turn every contentious issue into a moral confrontation is divisive. One way of fortifying people’s self-esteem is praising them as smart, public-spirited and virtuous. But an easier way is to portray the “other side” as scum: The more scummy “they” are, the more superior “we” are. This logic governs the political conversation of both left and right, especially talk radio, cable channels and the blogosphere.

Unlike economic benefits, psychic benefits can be dispensed without going through Congress. Mere talk does the trick. Shrillness and venom are the coin of the realm. The opposition cannot simply be mistaken. It must be evil, selfish, racist, unpatriotic, immoral or just stupid. A culture of self-righteousness reigns across the political spectrum. Stridency from one feeds the other. Political polarization deepens; compromise becomes harder. How can anyone negotiate if the other side is so extreme?