The Supreme Court is set to hear arguments today on the most important abortion rights case in more than 20 years. Texas abortion providers are challenging provisions of a sweeping anti-choice law passed in 2013 that has already shuttered about half of the state’s roughly 40 abortion clinics. With Justice Antonin Scalia’s death, the case faces the possibility of a 4-4 deadlock, which would leave a lower court’s decision upholding the restrictions in place, although it would not set a national precedent.