At a time when most state budgets are facing massive deficits, it doesn’t make sense to ignore any potential new revenue. And when it comes to sales taxes on Internet sales, the missing revenue could mean $200 million or more a year for larger states. Beyond helping budgets, collecting the sales tax is an issue of fairness.

A recent agreement in California suggests the 45 states with a sales tax might soon be receiving hundreds of millions of dollars that have leaked, legally, from tax revenues, while also helping local businesses compete with Internet merchants. A 2009 University of Tennessee study estimated uncollected sales taxes for Internet sales this year at $11.3 billion. That’s a lot of money that states need for social services and infrastructure work.

After years of wrangling, the battle between giant Internet retailers and state governments over the collection of sales taxes could be ending.

A sales tax loophole has existed since 1992, when the Supreme Court ruled that merchants without a physical pres-ence in a state did not have to charge sales tax. At that time, the case involved catalog sales.

A battle between Web retail giant Amazon and the state of California had been heating up recently. But earlier this month, an agreement emerged that will require Amazon to begin collecting sales taxes on purchases made by Californians, beginning in September 2012.

Earlier this year, California passed a law requiring sales tax to be collected by Internet companies. In response, Amazon spent about $5 million to force a repeal of the law.

Similar efforts have been happening in other states.

For a decade or more, so-called brick-and-mortar stores on Main Street or in malls have battled the price advantage enjoyed by their Internet-based competitors that have not been required to charge sales tax. That inequity was allowed to remain in place despite various attempts to have a law passed in Congress mandating tax collection by Internet retailers. For their part, Internet retailers complained that state and local sales taxes were complicated and that collection would be a burden. While it’s true that sales tax rules and rates vary widely, it’s just as true that the computer programming talent that built the Amazon empire could surely handle the intricacies of thousands of different sales tax figures.

As the lingering recession has battered state budgets, the Internet sales tax issue has moved beyond being a matter of fairness to an issue of dollars and cents, with states missing out on $10 billion or more a year of uncollected sales taxes related to Internet purchases.

In California, where the recent breakthrough occurred, assuming the deal is signed by Gov. Jerry Brown, it is estimated that the state treasury could gain $317 million a year if sales tax on Internet purchases was being collected.

Other states, including Pennsylvania, should begin — or renew — their own efforts to collect sales tax on Internet transactions, based on the California deal. A better solution, however, would be a national agreement passed by Congress to enforce sales tax collection. Sen. Dick Durbin, D-Ill., has proposed just such a law, but it has not received much support, despite a national campaign by retailers, including Target and Wal-Mart, called the Main Street Fairness Coalition, which pushes the idea of fair competition and helping local merchants.

This issue should have been resolved years ago, but Amazon and other Internet retailers were able to hold off efforts to force them to charge and collect sales tax. Now, with the California agreement, there is hope that the missing tax revenue can be collected to help state budgets and to level the playing field between retailers with actual stores and those reaching customers through the Internet.