The Purpose of the Separation of Powers and Checks and Balances: 
TO PREVENT TYRANNY AND THE CONCENTRATION OF POWER IN ONE BRANCH

TO ENSURE THAT NO ONE BRANCH CAN ACT UNILATERALLY OR WITHOUT OVERSIGHT

TO PROMOTE A MORE BALANCED AND EFFECTIVE GOVERNMENT

So, when traveling to a different state in the US, by land or air, would one need to carry their:
* US birth certificate,
* marriage certificate (if name is different from that on birth certificate),
* driver’s license/real ID, and
* passport to be safe from being detained?

Asking for a friend.