How a 3-judge panel of the Sixth Circuit Court of Appeals will rule in six cases challenging gay marriage bans in 4 states is difficult to predict.

The judges on Wednesday will hear oral arguments in cases challenging marriage bans in Kentucky (2 cases), Michigan, Ohio (2 cases) and Tennessee – the most marriage cases that any federal circuit court has ever heard in a single day.

The Cincinnati-based Sixth Circuit is the third appeals court to review challenges to state bans since the U.S. Supreme Court's decision last year striking down a key provision of the Defense of Marriage Act (DOMA), which led to the federal government recognizing the legal marriages of gay couples.

Two out of the three judges are George W. Bush nominees – Jeffrey S. Sutton and Deborah L. Cook – while Martha Craig Daughtrey was nominated by Bill Clinton.

Sutton in 2011 shocked Republicans when he sided with the majority in a ruling that upheld the Obama administration's Affordable Care Act (ACA).

In comments to the AP, Mark Tushnet, a constitutional law professor at Harvard, said Sutton could again be the deciding vote.

“This is the kind of thing where you could see the conservative with a libertarian bent coming out in favor of gay marriage, but who knows?” he said. “Having done Obamacare and maybe screwed his own chances for the Supreme Court, Sutton may feel liberated to do what he thinks is the right thing and go for marriage equality, or he may try to rehabilitate himself and go against it.”

Carl Tobias, a law professor at the University of Richmond, said, given Sutton's unpredictability, that he could see the court ruling in either direction.

Former Ohio Governor Ted Strickland on Tuesday will headline a Cincinnati rally in support of marriage equality.

(Related: Opponents call for 4 days of prayer to ask 6th Circuit to uphold marriage bans in 4 states.)