Medicaid costs are escalating at an unsustainable rate, not just for the federal government but for states, too. This serious problem demands a focused solution, not federal rule changes that cut states' Medicaid funding at the expense of poor children, seniors and disabled people. Sadly, the government has opted to change the rules.

Federal Medicaid administrators have finalized seven new rules that in many cases will stop payments for services that Medicaid long has covered.

One rule would end federal support for care provided to poor and disabled children by public schools. These services include health screenings, medical care and transportation for special-needs children who get health services at school.

Another rule change that impacts foster children took effect last Monday. It will limit funds for case management in which a specialist coordinates the child's health, education and social services. Yet Medicaid requires case management for children who need it. Bottom line: The feds force states to provide a service, but don't cover the costs.

How will the new rules impact federal Medicaid funding? The cuts to state programs could surpass $50 billion over five years, according to a U.S. House committee report. States would struggle to cover those funding losses or be forced to drop the services.

Federal Medicaid administrators say the rules are an attempt to rein in states that have resorted to questionable financing practices. Yet the same administrators have to approve any state deviation from established federal rules.

What Medicaid should and shouldn't cover is a subject worthy of debate. Should it pay for busing disabled children to school? Or the salaries of hospital interns and residents who treat poor people? This vigorous debate, however, should take place in Congress. The decision shouldn't be made by Medicaid administrators and forced on states by federal mandate.

The funding losses will hurt society's most vulnerable people, and it couldn't come at a worse time. With the economy taking a downturn, states are struggling to balance budgets.

Congress already has delayed some of the Medicaid rules in question, but others are due to take effect in coming months.

Fortunately, both the House and Senate are considering measures to further stall the rules.

Indeed, Congress should be the decider on Medicaid policy changes as sweeping as these. Lawmakers, along with a new administration in 2009, also should address the larger problem of Medicaid's structure and financing.