Whatever the qualms about online gambling — nightmare situations, real and potential, are many — Uncle Sam is leaving a lot of money on the table. Over 10 years, legal online gambling could generate $42 billion in tax revenue, according to the Congressional Committee on Taxation.

Image Credit... Minh Uong/The New York Times

An estimated 1.8 million Americans played online poker last year, and some make a living at it. Because of the legal issues in the United States, online card rooms typically base their computer servers elsewhere, in places like Costa Rica or, in the case of Full Tilt, in the Channel Islands.

Online poker fans, including some with money frozen in accounts at Full Tilt, are among the most vocal proponents of legalization. “It’s the only industry on earth that is clamoring for the U.S. government to impose regulations,” says Bradley Cole, an online poker player in Oxford, Miss. Mr. Cole said he had about $5,000 in his Full Tilt account on Black Friday.

Oddly enough, Internet gambling is already legal in the nation’s capital. Earlier this year, the District of Columbia became the first jurisdiction in the United States to legalize it. Officials there said they hoped the move would bring in $13 million to $14 million a year in tax revenue. But Washington may only be the start. Several bills now working their way through the House of Representatives would give online poker the run of the country.

IN five-card poker, there are 2,598,960 possible hands. A four-of-a-kind is dealt once in about 4,000 hands, a royal flush once in 650,000. And yet aficionados say poker isn’t really a game of chance. Instead, they argue, it is a game of skill — of mathematical probabilities and human psychology, played with artful direction and misdirection. The answer to this one question — chance or skill? — may well set the course of the multibillion-dollar business of online poker.

Alfonse M. D’Amato, the former three-term senator from New York, is a longtime poker buff and chairman of the Poker Players Alliance, a trade group that lobbies on behalf of poker players. In an op-ed article in The Washington Post in April, he sharply criticized the Justice Department for corralling Full Tilt and the other sites. He argued that online poker has never been explicitly outlawed, in part because, unlike, say, craps, the outcome doesn’t depend purely on luck.