Short answer they wanted to do solo music, Zane was the first one to leave due to stress and anxiety while on tour in 2015 , but they did recently go on tour again :)
The states still had the freedom to create their own laws and have their own constitutions (as long as they don't go against by the Constitution). The states have reserved powers.
The rights of the individuals are respected mainly by being listed in the constitution's first ten amendments, or Bill of Rights.
The U.S was made when the 13 colonies declared their independence in 1776
