Works for drivers licenses. Even though driving laws and licensing requirements are different between the states, each state must accept the fact that a license issued by another state makes the individual a valid driver within their state. Even if there's a difference in requirements or other details. This is based on the "equal protection" aspect of the 14th Amendment. Now works for marriage licenses too. Each state must allow for issuance, and each state must respect, honor and recognize the licenses from all other states, even if the terms and laws of other states are different. This is also based on the "equal protection" aspect of the 14th Amendment. What about my license to carry a concealed weapon/firearm? The laws between the states vary, but in my state, I can apply for and obtain a license. Does/should it become invalid when I go to another state that has different laws and requirements? Or should it be respected, honored and recognized no matter what state I visit? Not only would that comply with the "equal protection" aspect of the 14th Amendment, it would also comply with the "keep and bear" aspect of the 2nd. Emotions aside (no really, TRY putting them aside), is there a problem or flaw in this reasoning?