In their zeal to overturn the DOMA, proponents of gay marriage* are arguing that a license of marriage in one state should be honored and given equal rights in the other states.
As a rule, these folks are also pretty liberal in their views. Not always, of course... MattG is a supporter, as are a number of other "non-liberal" folks... but by and large it's not the "right wing conservative" that is pushing for a repeal of DOMA.
At any rate, wouldn't it be a hoot and a half if, in their efforts, they actually WON? Because then one could easily argue "Well, then every state must recognize a Concealed Carry Permit from every other state" and we'd have Constitutional Carry without much effort at all.
* Full disclosure: I'm all in favor of same sex marriages being recognized as equal to heterosexual marriage.