The Supreme Court is widely expected to legalize same-sex marriage nationwide by the end of the month. But if the Court defies those predictions—and, hey, it wouldn’t be the first time—its ruling would open up a new front in one of the most polarizing culture wars of the past 20 years.

A high court ruling against same-sex marriage would plunge millions of gay couples into a chaotic patchwork of conflicting, uncertain state laws, leaving their marriage rights in limbo—and igniting a new political firestorm too big for 2016 contenders to ignore.

Legal experts agree that the fallout from a ruling against same-sex marriage would amount to legal chaos. The right to marry would disappear in several states where it exists, deepening the divide between states and, in some cases, even creating uneven playing fields within the same state.

But it’s impossible to know where, exactly, same-sex marriage would remain legal, where it would disappear temporarily, and where it would disappear forever.