Facing the wrath of some sports fans, state Attorney General Eric Schneiderman says he's standing behind his legal bid to bar two fantasy sports sites in New York. Josh Robin filed the following report.

In sports, winning requires skill. Let's face it: luck sometimes plays a role, too.

Arguably, both skill and luck figure in to a new modern pasttime: online fantasy sports. Separating how much is what experts say is key to this case. So is sussing out sometimes confusing state law.

"It's absolutely nebulous," said Marc Edelman, a sports gaming expert at Baruch College. "As compared to tests in other states, New York's is the most nebulous. There are some states that say if you can show the game is 51 percent skill, you're OK. There are other states that say there's any chance whatsoever, you're not ok. New York is in this middle ground."

Edelman has given legal advice to fantasy sports firms but is not employed by DraftKings and FanDuel, the two firms Schneiderman says are illegal.

Edelman says this fight could have far-reaching consequences beyond the New Yorkers who consider fantasy sports a cherished hobby. A bad ruling in New York could doom a billion-dollar-plus industry nationwide.

"Under federal law, if a contest violates state law, it serves as a predicate for an offense," Edelman said.

After an unrelated event Wednesday, Schneiderman said he's just calling balls and strikes. His office is also looking into daily fantasy sports at Yahoo.

"I think we will be able to demonstrate that we have a very strong, very compelling case, and the law has to be enforced," the state attorney general said.

The sites are fighting the charges. Yahoo says it believes its product is lawful.

Schneiderman has received campaign donations from legal, regulated gaming interests. Sports gambling is, of course, illegal in New York State, but fantasy sports sites are seen as competitors for those interests in the entertainment market.

"The decisions are made by lawyers based on the merits of each case, and it's never affected the merits of our decision-making," Schneiderman said. "And it's a very small amount of money, considering the millions of dollars I've had to raise."

Governor Andrew Cuomo, Schneiderman's predecessor, says the investigation should continue.

"I understand the question that he's raising legally. I think it's a legitimate question," the governor said.

New state law could settle the matter, but on deck is a court hearing next week.