The move comes the same day the U.S. Supreme Court began hearing arguments on the constitutionality of California’s Proposition 8, which banned same-sex marriage in the state.

A news release from Lowenthal’s office said the Architect of the Capitol and the House historian informed the congressman that he’s likely the first member of Congress to “formally display a Pride flag outside his Congressional office.”

Permanent fixtures outside each lawmaker’s office can hold up to three flags. While one is traditionally used for Old Glory and another for the member’s state flag, the third can hold a personally selected flag.

Lowenthal said Tuesday of the colorful item: “My intention is to fly this flag until marriage equality is the law of the land.”

Photo: Courtesy of office of Rep. Alan Lowenthal