Three senior Senate Republicans on Monday proposed an alternative to ObamaCare that would replace “job-crushing” federal mandates with a voluntary system led by the states. The legislative blueprint from Sens. Richard Burr (N.C.), Tom Coburn (Okla.) and Orrin Hatch (Utah) would eliminate all of the healthcare law’s federal rules, including the unpopular requirement to purchase insurance under the threat of penalty. But the GOP proposal, known as the Patient Choice, Affordability, Responsibility and Empowerment (CARE) Act, would also weaken one of ObamaCare’s most popular provisions, by giving insurers an opening to discriminate against people with pre-existing conditions. The CARE Act...