The roots of this crisis go back to the Carter administration. That was when government officials, egged on by left-wing activists, began accusing mortgage lenders of racism and "redlining" because urban blacks were being denied mortgages at a higher rate than suburban whites. The pressure to make more loans to minorities (read: to borrowers with weak credit histories) became relentless. Congress passed the Community Reinvestment Act, empowering regulators to punish banks that failed to "meet the credit needs" of "low-income, minority, and distressed neighborhoods." Lenders responded by loosening their underwriting standards and making increasingly shoddy loans.
Jeff Jacoby, “Frank’s fingerprints are all over the financial fiasco”, Boston Globe.