WASHINGTON — The Supreme Court on Friday stripped away the nation’s constitutional protections for abortion that had stood for nearly a half-century. The decision by the court’s conservative majority overturned the landmark Roe v. Wade ruling and is expected to lead to abortion bans in roughly half the states.The ruling, unthinkable just a few years ago, was the culmination of decades of efforts by abortion opponents, made possible by an emboldened right side of the court fortified by three appointees of …