WASHINGTON — What if Congress enacts a federal ban on abortion? It’s no longer an outlandish question. While abortion rights are safe for the moment in California, a widely anticipated “red wave” of Republican success in the November midterm elections, followed by a possible GOP win in the 2024 presidential race, could lead to nationwide prohibition. Abortion rights advocates’ fears were stoked last month by Supreme Court decisions that cut deeply against California’s liberal grain — not only on reproductive freedom, but also guns and climate change. The rulings drew angry promises from state …