BURBANK, Calif. – At the center of the Supreme Court’s pre-eminent case of the term — the one that holds the potential for redefining marriage in America — are a couple whose chief attribute is how conventional they strive to be.

Jeff Zarrillo, 39, manages the big multiplex movie theater in downtown Burbank, and Paul Katami, 40, is a fitness instructor. They have lived for nine years in a small but handsome house just past the second speed bump on a quiet, suburban street. It is a neighborhood where American flags are plentiful and interest in the school board election appears high.

When the Supreme Court hears the men’s challenge to California’s ban on same-sex marriage on March 26, there is a good possibility that their names will not even be mentioned.

What the court is interested in, among other things, is whether the constitutional guarantee of equal protection contained in the 14th Amendment, adopted in 1868, requires extending the right of marriage to those who want to wed someone of the same sex.

What Zarrillo and Katami are interested in is getting married.

“He’s the person I want to spend the rest of my life with,” Zarrillo said, as the sounds of an action movie rumbled through the walls of his office at the theater. “I want to be able to call him my husband. I want to marry him, just like my parents are married.”

Their lawsuit against Proposition 8, which California voters approved in 2008 to restrict marriage to a man and a woman, is nearly four years old. Both Zarrillo and Katami say they have grown accustomed to talking to strangers about each other, about love, about their desire to get married and raise children.

Still, until now, the men most closely identified with the court challenge were not the Californians but their attorneys, Ted Olson and David Boies.

Competitors in Bush v. Gore, it was their political-odd-couple collaboration to get the issue of same-sex marriage before the Supreme Court that earned a Newsweek cover, television interviews and front-page headlines across the country.

“Just the other day,” Zarrillo said, “I was talking to somebody about our case and he said, ‘Wait. You mean you’re in the Ted Olson case?’ “

“But really, they do deserve all the credit,” Zarrillo continued with a laugh. “I mean, they’ve done everything to get us here.”

But every lawsuit requires real plaintiffs, people with a tangible interest in the outcome: The men — along with a lesbian couple from the Bay area, Kris Perry and Sandy Stier, who also are named in the suit — would like to get married. Proposition 8 says they may not.

“They are a real couple,” said Adam Umhoefer, executive director of the American Foundation for Equal Rights, the group organized to challenge Prop 8. “They live in a house in the suburbs, with kids going by on skateboards and playing catch in the front yard, and they’ve got their two dogs and they go to work. It’s so remarkably normal in a way, and I think that’s what’s so powerful about it.

“How can you deny these two?”

But four-fifths of the states — most through voter-approved constitutional amendments — would. In a brief filed to the Supreme Court, 20 of them said that “legitimate justifications for traditional marriage are long-established, even if sometimes forgotten or deemed old-fashioned.”

In their brief, the attorneys for Zarrillo and Katami said their clients agree with the proponents of Prop 8 “that marriage is a unique, venerable, and essential institution. They simply want to be part of it.”

California voters approved Prop 8 after the state Supreme Court ruled 4-3 that same-sex couples could not be denied the right to marry. It passed with 52 percent of the vote.

Almost immediately, liberal activists such as Rob and Michele Reiner began organizing a legal challenge. The surprise came when they were told the issue might interest Olson, a prolific Supreme Court practitioner, former solicitor general under President George W. Bush and stalwart of the conservative legal establishment.

He teamed up with Boies to organize a challenge that would try not just to overturn Prop 8 but also to establish that the Constitution requires making marriage available to all. And that would involve finding the right plaintiffs.

Zarrillo and Katami had no reason to believe it would be them.

They have been a couple for 12 years, politically aware, especially of Prop 8, but hardly activists.

Zarrillo is a “Jersey boy,” raised in the township of Brick, N.J., and a graduate of Montclair State University. He started taking tickets at the local movie house in college, and now AMC is the only company he has ever worked for.

He moved to California after college and now manages the 16-screen theater in downtown Burbank, the busiest on the West Coast.

His coming out was slow, even though he said he knew in high school that he was gay. Even after coming to California he dated women. He met Katami online.

When the two decided to move in together, Katami had one condition.

“I told him that I wouldn’t do it until he told his parents,” Katami said in an interview, sitting at the couple’s dining-room table. “I had been through all that with someone else – separate phone lines and everything. I wasn’t going to do that again.”

Zarrillo booked a flight to New Jersey that night. He should not have been concerned.

As his father, Dominick, wrote in a first-person Father’s Day article published last year in The New York Times: “We told him that we already knew, and that we really liked Paul, and that we were happy for him. We laughed about how scared he had been to tell us, and after that it was Jeff and Paul, Paul and Jeff.”

Katami grew up in San Francisco, and he, too, mostly kept the secret of his sexuality through high school. He figured his family suspected and never felt the need for a sit-down explanation. “I just decided one day I would say, ‘I have a boyfriend, and I’m bringing him home for Thanksgiving,’ and that would be it,” he said.

After getting a master’s of fine arts at UCLA, Katami tried his hand at acting and eventually settled on training. He developed a core-exercise apparatus called the Katamibar that he introduced via infomercials, and he has a full line of training videos online.

Neither was disappointed that the Supreme Court decided to take the case. “This is what we hoped would happen from the beginning,” Zarrillo said. “This is what we signed on for.”