In trying to divine what the U.S. Supreme Court might do when asked to step into Round Two of the Affordable Care Act battle, it’s only safe to say — as one academic put it — “All bets are off.”

Round One ended in 2012, when the justices, voting 5-4, upheld the constitutionality of the act’s individual mandate to buy insurance. Round Two is the conservative attack on an Internal Revenue Service rule interpreting the law’s subsidies for insurance bought on exchanges “established by the state” to include those established instead by the federal government.