Poker is mainly a game of skill, not chance, a federal judge ruled Tuesday, tossing out the conviction of a New York man who ran a poker club advertised by word of mouth and text messages.

The ruling is a legal victory for Lawrence Dicristina, a businessman who sold electric bicycles and operated a poker club in the back room of his Staten Island warehouse.

But legal experts say it also undercuts one of three federal laws used in the past to shut down online poker in the U.S. The Justice Department concluded earlier this year that another of the laws should not apply to online poker.

Dicristina was charged with violating the Illegal Gambling Business Act, a 1970s-era federal law intended to crack down on organized crime. Its definition of gambling lists several forms -- including slot machines, lotteries, and bookmaking -- that his lawyers argued were games of chance.

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Director Douglas Tirola of the documentary, "All In … The Poker Movie," and 2003 World Series Poker Champion Chris Moneymaker talk about the evolution of the game and the increasing interest in it.

Poker, they argued, is primarily a game of skill and therefore isn't covered by the federal law. On Tuesday, Federal District Court Judge Jack Weinstein agreed.

"In poker," he wrote, "increased proficiency boosts a player's chance of winning and affects the outcome of individual hands as well as a series of hands. Expert poker players draw on an array of talents, including facility with numbers, knowledge of human psychology, and powers of observation and deception."

His 120-page opinion included charts and graphs showing how players more accomplished at such skills as bluffing consistently tend to beat inexperienced players.

What's more, Dicristina's lawyers argued, forms of gambling typically covered by federal law involve betting against casinos running the games, which manipulate the odds of winning. A poker player, by contrast, bets solely against other players, not the house.

They also contended that most poker hands are won by inducing opponents to fold, with the cards never revealed or compared. By bluffing, they told the judge, a player minimizes the importance of the luck of the draw.

“We have patiently waited for the right opportunity to raise the issue in federal court,” said John Pappas, executive director of the Poker Players Alliance, which aided in Dicristina’s defense and helped formulate the winning legal arguments. “Today’s federal court ruling is a major victory for the game of poker and the millions of Americans who enjoy playing it.”

Weinstein noted that poker has a long history in the United States, "embraced by many of our political leaders and other public figures," including former Supreme Court Justices William O. Douglas, "a regular at President Franklin Roosevelt's poker parties," and Fred Vinson, who played the game with President Harry S. Truman.

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Legal experts said Tuesday's ruling could undercut the ability to restrict online poker and could encourage Congress to pass pending legislation that would permit the game to be played online under federal regulation.

In Tuesday's ruling, Weinstein said federal prosecutors can still use racketeering laws to go after games run by organized crime figures. And he said states can prohibit poker under their own laws.

Pete Williams is NBC News' justice correspondent.

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