By the 70s crime had skyrocketed and it was clear that they had gone too far. But instead of issuing a mea culpa and reexamining past rulings, the various courts started allowing prosecutors to claim broad new powers and take extremely aggressive tactics.
By this point there's no real way to fix it. The legal system is based strongly on precedent. It can't just undo major rulings of the past and replace the with something sane.