While the high-profile, Ted Olson- and David Boies-managed legal fight against California’s Proposition 8 captures headlines, a carefully planned case quietly underway in Massachusetts federal court could be the gay marriage test with the greatest national impact.

The challenge, Gill v. Office of Personnel Management, is one of four lawsuits in different parts of the country that ask federal courts to strike down all or parts of the 1996 federal Defense of Marriage Act (DOMA). The suits, and the Gill case in particular, according to advocates and scholars closely watching their progress, are just the opening shots in a struggle destined for the U.S. Supreme Court.