We have come a long way since the days when banks wrote off entire minority communities, denying loans and mortgages to creditworthy people because of their race or where they lived. But perhaps not far enough. A recent Federal Reserve study shows that black Americans are three times as likely as whites to be signed up for high-cost "subprime" mortgages that often force borrowers into default.

Lenders typically argue that critics are confusing risk with race and point out that the scores on which they base mortgage rates are computed automatically, based on standardized consumer credit information. It is hard to judge these arguments because so much credit information is kept private. Lenders typically refuse to release data on individual credit scores or disclose their own risk analysis.

But it seems likely at this point that uninformed borrowers are being herded into higher-cost mortgages more frequently than necessary. That is probably due at least in part to the complexity of the current lending system. Mortgages are now sold mainly through mortgage brokers, who are virtually unregulated. This system has spread access to mortgages to communities that were once shut out. But brokers themselves have no legal responsibility to give borrowers the best rate -- or even a fair rate, for that matter.

Sellers of mortgages often earn their money by marking up mortgage rates and adding fees and penalties, some of which can be onerous. That poses a particular danger for unsophisticated borrowers. Even well-educated consumers have difficulty finding out how their individual mortgage rates are calculated and what the various fees are.