The Supreme Court is scheduled to hear arguments this week on issues related to same-sex marriage. (Joshua Roberts/Reuters)

When the Supreme Court hears arguments Tuesday on same-sex marriage, they will come from four people that many Americans probably have never heard of — John Bursch, Joseph Whalen, Mary Bonauto and Douglas Hallward-Driemeier — and Solicitor General Donald Verrilli.

But it will be through their voices — Bonauto, Verrilli and Hallward-Driemeier for same-sex marriage, and Bursch and Whalen arguing for state bans against it — that the court will decide whether gay and lesbian couples can marry and have their marriages recognized in 50 states.

Hallward-Driemeier and Bonauto were selected last month after a legal “bake-off” in Michigan to decide who would advocate for gay marriage before the high court. Details about the bake-off remain under wraps, but those familiar with the process say that in order to select the best representative before the high court, lawyers typically negotiate among themselves.

The winners are picked based on several factors, including how they perform in mock trials as well as how deeply lawyers have been involved in the issue to be heard.

According to briefs filed with the court, more than 40 lawyers worked on behalf of the same-sex couples in Ohio, Kentucky, Michigan and Tennessee. Those four cases seeking recognition of their marriages have been consolidated into one before the high court.

Joseph Whalen is an associate solicitor general in Tennessee. He will handle oral arguments on whether the 14th Amendment requires states to recognize same-sex marriages performed in other states that permit them. (Mark Humphrey/AP)

“Whenever you have multiple parties who have to come together and select one person to do the argument, it becomes a tricky situation,” said Pratik Shah, a former assistant to the U.S. Solicitor General who co-heads the Supreme Court and appellate practice at law firm Akin Gump. “My guess is it was a negotiation process and a decision they came to, probably not easily.”

Shah, who was not personally involved in the selection, said he once watched two lawyers settle the matter by flipping a coin.

How Bursch and Whalen were selected is less clear, and their offices and allies are more reluctant to speak in detail about how they were brought into the case. Whalen’s office declined to elaborate on his selection or preparation for Tuesday’s arguments.

In an interview with Washington Post reporters, Michigan Attorney General Bill Schuette, whose office hired Bursch to represent the state before the Supreme Court, said the decision to tap Bursch was “a discussion among the states, in agreeable fashion. It just kind of occurred in an orderly process.” Bursch said, “There was no contentiousness or anything like that.”

Hallward-Driemeier and Bonauto come to the case with different backgrounds — each a veteran in his and her field but each venturing into new territory in this case.

Hallward-Driemeier is part of an elite group known in legal circles as the Supreme Court bar, which consists of a few dozen lawyers in the country. Many of them, like Hallward-Driemeier, worked in the Solicitor General’s office before joining a top corporate law firm. Each has argued more cases before the Supreme Court than the vast majority of lawyers will in their careers. Hallward-Driemeier was assistant to the Solicitor General from 2004 to 2009 and leads the Supreme Court and appellate practice at the international law firm Ropes & Gray.

Bonauto will be appearing before the Supreme Court for the first time. She works at the nonprofit Gay & Lesbian Advocates & Defenders in Boston and is arguably the most esteemed legal advocate in the lesbian, gay, bisexual and transgender movement. Bonauto became a pioneer for marriage equality decades before it became a mainstream political issue. She is credited with outlining and executing the long-term legal strategy to achieve marriage equality by challenging state laws. She argued and won the nation’s first case legalizing same-sex marriage, in Massachusetts in 2003, and brought the Vermont case that prompted the state legislature in 2000 to enact civil unions for same-sex couples.

Mary Bonauto is credited with outlining and executing the long-term legal strategy to achieve marriage equality by challenging state laws. Last year she was awarded a “genius grant” from the MacArthur Foundation. (John D. and Catherine T. MacArthur Foundation/AP)

On a call Tuesday with reporters, Bonauto said she feels as if she has “been preparing for an argument like this for well over a decade and looking forward to it.”

Hallward-Driemeier has argued 15 cases before the high court, 13 of which he did on behalf of the federal government while at the Solicitor General’s office. Of the two he has argued since joining private practice, he has lost one (a 2014 bankruptcy case in which he represented the Executive Benefits Insurance Agency), and argued another (a bankruptcy case in which he represented Hyde Park Savings Bank) that has yet to be decided.

He is a relative newcomer to the same-sex marriage cause, getting involved in November, the day after the U.S. Court of Appeals for the 6th Circuit upheld the four states’ same-sex marriage bans. He was approached by his law school classmate Chris Stoll, a lawyer at the National Center for Lesbian Rights.

Hallward-Driemeier said he is “truly honored to be sharing the podium with Mary Bonauto,” and added that “there are so many people who have been working on this issue for so long, and there’s so much wisdom they share, it’s been a collaborative effort.”

Preparation for a Supreme Court appearance is intense, even for those with the most experience. It involves months of moot courts and round-the-clock strategy sessions.

On Tuesday, the court will hear arguments on two questions: first, whether the Constitution’s 14th Amendment requires states to allow same-sex couples to marry; and second, whether that amendment requires states to recognize same-sex marriages that were performed in other states where it is permitted. Bonauto will argue the first question; Hallward-Driemeier, the second. Bonauto will be joined by Verrilli, the federal government’s top lawyer at the Supreme Court. He has been in the position since 2009 and argues about half a dozen cases a year before the court.

Bonauto is going up against Bursch, a former Michigan solicitor general from 2011 to 2013 who has experience in front of the Supreme Court. He has argued eight cases before the high court and has won most of them, including the 2014 case in which the justices upheld Michigan’s ban on the use of race in public university admissions. Bursch, a partner and head of the Supreme Court and appellate practice at Michigan law firm Warner Norcross, is working independently from the firm on this case.

When asked about Bursch on the call with reporters, Bonauto simply said, “I look forward to meeting him.”

On the second question, Hallward-Driemeier will be opposite Whalen, an associate solicitor general for Tennessee, who will represent Tennessee, Kentucky and Ohio. It will be Whalen’s first time before the Supreme Court. The Tennessee attorney general’s office declined to elaborate on Whalen’s role but provided information about his background.

Whalen began his legal career in Massachusetts as an assistant district attorney for Middlesex County from 1985 to 1990 before briefly going into private practice. He later returned to the public sphere as assistant attorney general for Massachusetts from 1993 to 1999. His career then shifted to Tennessee, where he served as assistant attorney general from 1999 to 2004 and associate solicitor general from 2004 to 2014. He was acting solicitor general from February to October 2014 and associate solicitor general beginning in November.

Bob Barnes and Sandhya Somashekhar contributed to this report.