The marriage amendment was designed to prevent unelected judges from overruling state legislatures and voters and manufacturing by judicial decree a right to same-sex marriage, such as the Massachusetts Supreme Judicial Court did in 2003.

In a statement submitted to the Congressional Record, McCain acknowledged this and other extra-legislative challenges to traditional marriage, but said: "I do not agree that all the above circumstances have made it necessary to usurp from the states, by means of an amendment to the federal Constitution, their traditional role in regulating marriage. I'm reluctant to abandon the federalism that is part of the essence of conservative political thought in this country."

On one day -- June 7 -- so great was his commitment to federalism he could not allow the Senate to even vote on an amendment that would require a two-thirds majority in both houses and then ratification by three-fourths of the states before it could become law.

On another day -- June 8 -- McCain's commitment to federalism was a bit more flexible. Now the threat to state's rights was an effort to create a new nation out of one segment of the population of one state of the union.

"I have serious reservations about the wisdom of this legislation," McCain said on the Senate floor. "I am sure that the sponsors have good intentions, but I cannot turn away from the fact this bill would lead to the creation of a new nation based exclusively -- not primarily, not in part, but exclusively -- on race. In fact, any person with even a drop of Hawaiian blood would qualify to vote on the establishment of this new, legislatively created entity that would then negotiate with the Federal government of the United States and the state of Hawaii on potentially unlimited topics."

Nonetheless, McCain voted for cloture on this bill -- which, after all, he had already shepherded through the Indian Affairs Committee, which he then chaired. The cloture vote failed with 56 votes, just four short of the needed 60. Unlike the marriage amendment, this bill would become law with simple majority votes in both houses and the president's signature. (It won just such a vote in the House in October, and has been reintroduced in the Democrat-controlled Senate.)

McCain's deference to what liberal's wanted trumped his vaunted deference to federalism. When push comes to shove, would it be any different if he becomes president?