A supermajority of at least seven Supreme Court Justices should be required to overturn laws as unconstitutional. When a law is passed by Congress or a state legislature, and signed by a governor or the president, it has already been deemed Constitutional by all those who approved it. If the law is to be deemed unconstitutional, it shouldn’t be a close call. It should be obvious; hence the necessity for a supermajority.
From Slate’s Hive, among their readers’ best ideas on the How To Fix The Constitution.