Its the first legal test of New Jersey's sports wagering law.

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Four professional leagues and the NCAA sued Governor Christie in August after he vowed to defy the federal ban on sports betting. Lawyers for both sides had their day in court Tuesday.

After about an hour of arguments, a judge said he will issued a written ruling by Friday.

"This is a big decision for the state, it would give a big revenue boost to the state's casinos and racetracks that so desperately need it. We are talking about billions of dollars potentially," said Senator Ray Lesniak (D-Union), sponsor of New Jersey's sports betting legislation.

"There's no evidence that gambling has hurt the sports leagues and their reputation," said Theodore Olson, a former U.S. solicitor general who has joined the state's legal team. "All evidence shows sports have grown in this country alongside the growth of gambling, some legal, some not legal. Illegal gambling on the Super Bowl has made the Super Bowl the most watched event on TV in the world."

The leagues argue it would hurt them and their reputation.

"There will be greater suspicion about all of the normal incidents in the game, every dropped pass, every missed free throw" if sports gambling is allowed to spread, plaintiffs' attorney Jeffrey Mishkin argued. "They're our games. That gives us a personal stake, and that gives us standing."

But, Lesniak disagrees. "The fact of the matter is gambling on sports, whether legal or illegal takes place across the country and Nevada is the state where people flock during Final Four weekend and on Super Bowl weekend...Atlantic City is a ghost town, that would be reversed if we had legalized sports betting, it would not hurt the leagues," he said.

Mishkin said, far from converting illegal gamblers into legal gamblers, the opposite would occur.

"Legalizing gambling doesn't regulate illegal gambling, it fuels more gambling," he said. "You're going to create a whole new category of gamblers. Then they'll find out they can get better odds with the illegal bookie, and that their earnings aren't going to be reported with the illegal bookie."

If the judge sides with the state, the leagues are expected to appeal immediately.

"This is a big deal for us and I believe and am confident that we will be successful," said Lesniak."I look forward to setting the stage for New Jersey to legally regulate sports wagering without the shadow of an unfair federal ban hanging over our state."

(The Associated Press contributed to this report)