Reason.com:  The 10th Amendment to the Constitution is like the skinny teenage girl who blossoms over the summer and suddenly finds herself besieged by suitors. Once ignored, it has found a host of champions among Republican presidential candidates who are competing to show their devotion.

The amendment contains just one sentence: “The powers not delegated to the United States by the Constitution, nor prohibited by it to the States, are reserved to the States respectively, or to the people.”

It is a bulwark of federalism, which allows states the freedom to adopt different policies reflecting their peculiar circumstances. It was meant as a check on those who would demand uniform practices from one end of America to the other.