Sen. Leahy, Democrat of Gotham City?

With public approval ratings hovering around a disappointing 20 percent, Congress could use a super hero in its ranks.

But lawmakers may have to settle on a cameo appearance in a Hollywood action film by one of their own: Sen. Patrick Leahy of Vermont.

The seven-term Democrat makes an appearance in this summer's hot ticket "The Dark Knight Rises," the third installment in producer-director Christopher Nolan's successful Batman film trilogy, slated to open July 20.

Leahy, who chairs the Senate Judiciary Committee, is no stranger to the silver screen. He made cameo appearances in two previous Batman movies, and scored a small speaking part in "The Dark Knight."

Spokesman David Carle told CNN his boss has had a "lifelong affinity for the Batman character, dating back to his first library card at age four and throughout an earlier career as a successful crime-fighting prosecutor."

Leahy wrote the preface for a book about Batman several years ago, and voiced a brief scene in the Batman animated TV series. He donates all his "Batman" fees and royalty checks to the children's wing of the Kellogg-Hubbard library in Montpelier, Vt., which he credits with stoking his childhood love of reading.

If the acting thing doesn't work out, Leahy is well-positioned to keep his day job in the Senate. He was re-elected with 64 percent of the vote in 2010.

"The Dark Knight Rises" is produced by WarnerBros. Both WarnerBros and CNN are owned by Time Warner.