According to the Center on Budget and Policy Priorities (pdf),
Many policymakers continue to claim that the 1996 welfare reform law which created the Temporary Assistance for Needy Families (TANF) program was a major success. They see the TANF program’s design and block grant structure as a model for the reform of other safety net programs.
TANF’s record over the last 15 years shows, however, that its role as a safety net has declined sharply over time. In 1996, for every 100 families with children living in poverty, TANF provided cash aid to 68 families. By 2010, it provided cash assistance to only 27 such families for every 100 in poverty. . .
The 1996 welfare law gave states broad flexibility over how to design their TANF programs and allocate state and federal TANF funds. This is one reason why the decline in TANF-to-poverty ratios was much more pronounced in some states than others — some states adopted very restrictive policies and made it difficult for families to initially receive or to continue receiving assistance. For example, Georgia and California had similar ratios in 1994-95 (98 and 97, respectively) but very dissimilar ratios by 2009-10 (8 and 66, respectively)