WASHINGTON – The Obama administration has quietly opened the door for states to seek major changes in how they meet federal welfare-to-work requirements for some of their poorest residents, and leading conservatives are crying foul.

In a memo to states issued with little notice late Thursday, the federal Health and Human Services Department said it is interested in approving state experiments that will help "find more effective mechanisms for helping families succeed in employment."

States will not be able to escape the work requirements of the landmark 1996 federal welfare reform law, the administration said, but they may get federal approval to try to accomplish the same goals by using different methods than those spelled out in the legislation.