The federal government's challenge of the constitutionality of California's voter-initiated gay-marriage ban is a welcome development in the Obama administration's evolving view on marriage equality.

But the friend-of-the-court brief the administration filed in the pending U.S. Supreme Court case also is an effort to have it both ways.

The legal argument endorses gay marriage and makes a strong case that California's ban is wrong, but it pulls a punch by not advocating for a broad ruling that would invalidate gay-marriage bans in other states, including Colorado.

Perhaps it's a strategic move designed to construct a middle-ground position for justices who might not be willing to go big on the question of gay marriage.

But it's also a missed opportunity for the administration to take a bold and the right position on a defining civil-rights issue of our times.

At issue is whether California's Proposition 8, passed in 2008 by voters on a 52-48 margin, violates constitutional guarantees of equal protection under the law.

The measure put a prohibition against gay marriage into the state constitution and effectively kicked the legs out from a state Supreme Court ruling that a previous gay-marriage ban was illegal.

Proposition 8 was declared unconstitutional by two lower federal courts, and will be argued before the Supreme Court on March 26.

The lawyers challenging the ban Theodore B. Olson and David Boies have asked the court to render a broad ruling at a time when support for gay marriage is at an all-time high.

In a recent poll, Californians backed same-sex marriage by a nearly two-to-one margin. In 2006, two years before Proposition 8 passed, the same poll showed only 44 percent of residents supported the idea.

While Supreme Court decisions shouldn't be driven by public opinion, to say they don't influence how far justices might be willing to go on a particular issue at a particular time would be to ignore reality.

And the reality is that American opinion on gay marriage has evolved quickly during the last several years, with a plurality now supporting it.

The country is ready for it. The administration is on board, at least insofar as the core tenets of equality go. And this case presents the right questions, framed in the right way.

The Supreme Court should find gay marriage is a basic civil right and rule broadly so state gay-marriage bans could be overturned.

At the recent Jefferson-Jackson Day dinner, Former Denver Mayor Wellington Webb made the case for overturning the 2006 Colorado constitutional amendment banning gay marriage. He is correct it is the right move for Colorado and the nation.

The time has come.

The Denver Post, March 5