Patrick Leahy, a Democrat from Vermont and the longest-serving member of the current Senate, is a Batman aficionado who's turned his fandom into philanthropy.

When he's not working in the Senate chambers in Washington, Leahy retreats to Gotham, where Batman fights cartoonish villains and mans the Batmobile.

Leahy has long advocated to end the use of landmines, and he told the Capitol Hill newspaper Roll Call that he placed copies of the comic on every senator's desk that year.

Leahy's first foray into screen acting -- something he does strictly when Batman is involved -- came in 1995, when he appeared in the critically reviled "Batman Forever." The same year, he voiced a character billed as "Territorial Governor" in "Batman: The Animated Series."

Since then, Leahy has appeared in nearly as many "Batman" films as the Caped Crusader himself.

In 2012, the library hung a plaque honoring Leahy, who staff called their "super hero."

Why Leahy loves Batman so

Leahy found Batman when he was a boy, but his love for the fictional hero is foundational to who he is and the lawmaker he became.

Batman instilled in Leahy a love of reading and promoting literacy and of delivering justice (though as a government servant, not a caped vigilante).

Leahy preferred Batman to other characters because, unlike the god-like Superman or the super-powered Spider-Man, Batman was just a man, albeit an extremely rich one, with "human strengths and human frailties." The danger Batman faced was different than that of other heroes -- his felt real, Leahy wrote in the DC collection foreword.

"The Batman prevailed through superior intellect and detective skills, through the freedoms afforded by great wealth and through sheer will," Leahy wrote in his foreword.