With oral arguments in the King v. Burwell lawsuit now set for early March, some policymakers and advisers are still fiercely debating whether the U.S. Supreme Court could rule that the federally facilitated marketplace's premium tax credits are retroactively illegal and require subsidy recipients to reimburse the cost of those credits. Health law supporters say that there is no possibility that the IRS would require repayments, while opponents are saying that Americans should be warned of the potential. Asked...