The states are taking legal action to prevent the Trump administration from dropping out of an agreement on how long it can hold children in federal facilities and under what standards.
Reports of children detained in crowded and unsanitary conditions long beyond the maximum legal limit have created a new controversy over the administration's immigration policies.
The president ended a policy that sent children to government-run facilities away from their parents, but critics say he created new problems, and kids already held may be there indefinitely.
