The second volume of Brian K. Vaughan's excellent superhero/politican series Ex Machina continues with an excess of fine storytelling in Tag.

Many writers might be content with a plot dealing with a psychokiller who's carving up dogs, kids and NSA agents, along with some subway graffiti that causes homicidal or suicidal tendencies in those who gaze too long at its intricate patterns. But no, Vaughan has a great deal more to explore in the human condition, and in this case his attention has focused on the issue of gay marriage.

Mitchell Hundred is the mayor of New York City. A former engineer and superhero known as the Great Machine, he gained his power (he can talk to and command machines) from a mysterious explosion a few years back. After a brief career as a costumed hero -- a job at which he wasn't all that good, really -- he determined to help people through a more legal means; of course, the fact that in this world Hundred prevented the second tower from being destroyed on 9/11 has given him a great deal of support at the polls.

Hundred vowed then to do whatever he could for the surviving first-responders who put their lives on the line at Ground Zero. So, when one of those heroic firefighters asks the mayor to perform a wedding ceremony, Hundred quickly agrees -- hesitating only briefly when he is told it will be a same-sex marriage.

It would be all too easy to let this become a parody of itself, a spoof of an ongoing legal issue throughout the United States. But Vaughan is too canny a writer for that, and he addresses it with a well-balanced blend of seriousness, humor and social debate. For, while Hundred might lack a great deal of political savvy, he does have convictions and will stand by them no matter how great the backlash.

I'm not sure, but I don't think Vaughan has written a bad book yet. Let's hope his winning streak continues.