On a sweltering late-spring afternoon, David Coffman, a local tax attorney, calls me to announce that he will be at The Stranger's front desk in less than 10 minutes. We had no plans to meet until that moment. In the lobby, Coffman, perspiring and beaming and wearing a gray suit, greets me with one hand and presents a framed certificate with the other. This certificate, the calligraphy reads, certifies him to argue cases before the United States Supreme Court.

Despite the impressive certification, Coffman has never actually argued before the nation's highest panel of judges. "I am a tax lawyer, not a constitutional litigator," he says. Nevertheless, he has a controversial plan, fueled by an almost messianic sense of urgent duty, to stand before the conservative- dominated court to argue for equal protection for gay couples who wish to marry.

On June 3, a week after he announced this plan, Coffman, 42, and his boyfriend, Matthew Mayne, 30, walked into the King County Courthouse and applied for a marriage license. The clerk, of course, promptly rejected the application under a 1998 state law that restricts marriage to one man and one woman (a law upheld in 2006, over the objections of gay-rights lawyers, by our state's supreme court).

His desired rejection letter in hand, Coffman began drafting a federal lawsuit that he intends to file within a few weeks in the U.S. District Court for the Western District of Washington, challenging his inability to get a marriage license. Win or lose, Coffman expects the case to be appealed to the Ninth Circuit Court of Appeals and eventually to the U.S. Supreme Court.

But Coffman's plan is exactly the kind of thing that LGBT legal groups have been working for years to prevent—and for good reason. Coffman's crusade could sacrifice a generation of gay-rights progress if the Supreme Court finds that separate (civil unions) is equal (to marriage). It's happened before. In 1896, the court found in the landmark case Plessy v. Ferguson that separate railcars for African Americans constituted equal treatment under the law, a decision that the court didn't reverse for almost 60 years. Fearing just this kind of scenario, groups such as Lambda Legal and the American Civil Liberties Union have instead litigated for gay marriage in a carefully orchestrated state-by-state strategy, identifying states with progressive courts and winning marriage rights in places such as Massachusetts (2005), California (2008), and Iowa (2009). Last year, and again in May, a coalition of national nonprofits issued a notice warning attorneys and gay couples that "pushing the federal government... or suing in states where the courts aren't ready is likely to lead to bad rulings."

But those requests didn't stop two other attorneys from filing a case in California, days before Coffman showed up to meet with me, in response to that state's supreme court upholding Proposition 8 (the ballot measure that restored a ban on same-sex marriage in California). The attorneys behind that suit are arguably the two best litigators in the nation, Ted Olson and David Boies, who represented George W. Bush and Al Gore, respectively, in the presidential-election recount case of 2000. Coffman says he doesn't trust Olson and Boies to argue the marriage case because they are straight and because Olson has represented extremely conservative causes in the past. Coffman also believes that by filing his case federally, it will become joined in with Olson and Boies's case, and they will ultimately be forced to work with him.

"My goal in this suit is that there will be a gay lawyer and someone who knows what has been going on for the last 20 years in the LGBT legal community," says Coffman.

Indeed, Coffman is not some random gay tax attorney. He sits on the board of Equal Rights Washington, he serves as the attorney for Seattle's gay pride parade, and he's teamed up in the past with Lambda Legal and Legal Voice (formerly Northwest Women's Law Center). Until now, Coffman has mostly walked in step with their ranks.

Jenny Pizer, director of the marriage project for Lambda Legal, is alarmed by Coffman's plans. So is Lisa Stone, executive director of Legal Voice. "I think these issues should be left to people in organizations that are deeply familiar with this area of the law," she said. "I tried to persuade him not to file the federal marriage suit."

Coffman acknowledges his case could fail, but he says he's done taking direction from national gay-rights groups that tell him to stay out of the way. There's no small amount of hubris involved in his gamble, but when challenged he offers a sort of Trojan-horse backup plan: If his case is, in fact, joined with that of Boies and Olson, Coffman says he might try to slow the case down, allowing time for President Barack Obama to appoint a more-progressive Supreme Court, thus increasing the chances of a favorable ruling on same-sex marriage. "One thing I am good at is throwing wrenches in the works," he says.