The Arizona Supreme Court’s ruling that most abortion is illegal in the state under an 1864 law throws a grenade into the election battle between President Joe Biden and former President Donald Trump.

Possession of the presidency may hinge on Arizona. It’s the third hardest toss-up state for Biden to win but has probably now been made easier for him. That’s because, for the past two years, abortion has helped Democrats whenever voters see it on a ballot or are reminded of it by the party.