A dozen states are applying for or entertaining work requirements and other restrictions on Medicaid — putting the lifeline for millions of poor Americans at risk. The precise consequences are difficult to project. But states seeking waivers for work requirements and other restrictions are estimating as much as an 8 percent or 15 percent cut to their Medicaid rolls. Not every Medicaid recipient, not even most, will be subjected to some of these harsher rules. But there is a sizable population who could soon face a real risk of losing health coverage.