In the 2014 elections, Republicans rode a wave of anti-Affordable Care Act sentiment to pick up nine Senate seats, the largest gain for either party since 1980. Newly elected Republicans such as Cory Gardner in Colorado and Steve Daines in Montana had hammered their Democratic opponents over the health care law during the campaign and promised to repeal it. Six years later, those senators are up for reelection. Not only is the law still around, but it’s gaining in popularity. What was once a winning strategy has become a political liability. Public sentiment about the ACA, also known as Obamacare, has shifted considerably during the Trump administration after Republicans tried but failed to repeal it. Now, in the midst of the COVID-19 pandemic and the ensuing economic crisis, which has led to the loss of jobs and health insurance for millions of people, health care again looks poised to be a key issue for voters this election. With competitive races in Colorado, Montana, Arizona, No...