The fight to save the Affordable Care Act met stiff resistance Tuesday from a panel of federal appeals court judges, who questioned whether the law's command that Americans buy health insurance is constitutional. The hearing sets the stage for a major decision later this summer that could impact health care benefits for millions of Americans and supercharge debate over the law in the heat of the 2020 campaign. If the Affordable Care Act is entirely invalidated, Americans would no longer receive protections for preexisting conditions, free preventive benefits coverage in all plans, mandatory acceptance of children on their parents' plans up to age 26, premium subsidies to buy policies on the exchange, and greater access to Medicaid in dozens of states. There is not currently a viable alternative to the law that can pass the House and Senate and get signed into law by President Trump. Republicans were unsuccessful at repealing and replacing the law in 2017 when they controlled both chambers and the White House. President Trump told ABC News in June that he will be unveiling a "phenomenal" health care plan within the next two months. With Tony to break it down is ABC News' John Parkinson.