Medicaid expansion in two dozen states remains one of the biggest hurdles to guaranteeing healthcare coverage after the rollout of ObamaCare, according to a new report from Families USA. Unless the remaining 23 states opt to expand the eligibility for the low-income insurance program, millions of people will continue to lack affordable coverage, the healthcare advocacy group warned. Many of those who remain uninsured fall in a coverage gap, where they make too little to qualify for tax credits but just above the current eligibility for Medicaid — unless they live in the 28 states that have agreed to the ObamaCare provision that brings a windfall of federal dollars to expand coverage.