In Mississippi, the poorest state in the nation, Republican lawmakers have loosened their decadelong resistance to expanding Medicaid and making health insurance available to roughly 200,000 of the state’s low-income residents. But some Republican leaders have said they will not approve a bill without a work requirement, a provision critics say could still leave the most vulnerable Mississippians behind. Medicaid expansion would bring coverage to state residents with incomes up to 138% of the federal poverty level — $20,783 for an individual, or $35,632 for a family of three. Currently, families of three with earnings up to 28% of the poverty level or $7,230 are eligible.