Meet Jim Obergefell: The Man Behind the Supreme Court Same-Sex Marriage Case

— -- Jim Obergefell's case will affect the marriage laws under which about 200 million Americans live, but the reason he sued his home state of Ohio was very personal: To make state bureaucracy recognize him as the widower of his late partner of 21 years, John Arthur.

They were legally married in Maryland just a few months before John died in 2013 -- but in 2004, Ohio voters had amended their state constitution to prohibit gay marriage from being "valid in or recognized by" the Buckeye State. In April, Obergefell's lawyer argued his case before the Supreme Court, which could issue its opinion as soon as today.

The potential monetary benefits for Obergefell of winning his lawsuit are small: He says Ohio’s recognition of his marriage would bring with it $255 in Social Security benefits, and potentially a small disability benefit when he retires.

"That was never our driving reason for doing this," he told ABC News, explaining that "it was all about our dignity and the respect we expect from the state we call home."

Still, proponents and opponents of same-sex marriage agree: More than one man's dignity is at stake. One of the two questions about gay marriage will be answered for the whole country by the Supreme Court based on whether the justices think Jim Obergefell is in the right.

The first question the high court was asked to consider is, "does the Constitution prohibit states from discriminating between gay and straight couples for purposes of marriage?" If the answer is yes, then Obergefell will get what he wants, of course.

But the court considered another question, too, and it's that question that Obergefell's case poses directly, because Obergefell and Arthur got married in a state where gay marriage was legal (Maryland) but lived somewhere it wasn't (Ohio). That second question is, "if the Constitution doesn't require states to grant marriage licenses to same-sex couples, does it at least require every state to recognize same-sex marriages consecrated in another state?"

If the Supreme Court says no to the first question it could still say "yes" to Obergefell, and force Ohio to recognize the Maryland marriage -- and write Jim Obergefell onto his husband’s death certificate.

Obergefell sat down with ABC News to tell the story of his long relationship, short marriage, and how he went from grieving partner to unlikely activist.

Video co-produced by ABC News' Jacquelyn De Phillips.