Most of the nation will rejoice when the Biden administration lifts the public health emergency that has been in force since March 2020. But when that moment comes — probably this summer, absent another surge — it could put many millions of adults and children currently on Medicaid at risk of losing health care coverage. Before the pandemic, state Medicaid agencies evaluated the eligibility of beneficiaries each year, removing from the rolls people living out of state or earning too much to qualify for the joint federal-state program. But to keep as many people as possible covered during the p…