When a federal appeals court meets in San Francisco on Monday for arguments on Proposition 8, legal analysts will be closely watching Judge Michael Hawkins, a moderate Democratic appointee whose vote is expected to be critical in the same-sex marriage case.

The randomly chosen three-judge panel of the U.S. 9th Circuit Court of Appeals also includes Judge Stephen Reinhardt, a California liberal appointed by President Carter, and Judge N. Randy Smith, a conservative from Idaho appointed by President George W. Bush.

“It’s a very favorable panel for the challengers to Proposition 8,” said Arthur Hellman, a University of Pittsburgh law professor and expert on the 9th Circuit.

Hawkins, an Arizonan appointed by President Clinton, “is the one to watch most closely,” Hellman said. He has sided with liberals in some key cases and will probably cast the decisive vote in the case if there is a split decision, Hellman and other analysts said.

The three-judge panel will need to rule on standing, whether the Defendant-Intervenors can actually intervene in this case if the lead officials in Calfornia decline to do so, as well as the underlying ruling. They will use Judge Walker’s thorough findings of fact as a guideline, though whether they accept all those facts will offer an insight into the potential ruling.

The hearing begins at 10am Pacific/1pm Eastern, and is expected to last two hours. The first hour will cover the standing issue, and as Calitics notes there’s a strong argument to be made that the D-I’s have no standing. Imperial County, CA is also attempting to appeal, but the Plaintiffs argue that marriage is a statewide and not a county issue.