PRACTICALLY FROM the moment in 2007 that officials in Annapolis discovered that Marylanders playing slot machines in Delaware and West Virginia were exporting about $150 million annually to the tax collectors of those two states, Maryland has mounted a breakneck campaign to build casinos and milk them for revenue. In a relatively small state, four casinos have opened; a fifth, in Baltimore, will be launched next year. Plans for the sixth — the glitzy jewel in the crown — were unveiled Friday when a state commission chose MGM Resorts to build, just south of the District line in Prince George’s County, a huge casino and resort , a Las Vegas-style pleasure palace dedicated to gambling, entertainment, celebrity-chef-branded restaurants and around-the-clock conspicuous consumption.

The MGM casino, a $925 million behemoth along the banks of the Potomac at National Harbor, is projected to open in 2016. Even allowing for exaggerated projections, the state could be raking in something approaching $1 billion in tax revenue from gambling by the end of this decade.

Whatever reservations some Marylanders (and we) had about gambling, state voters authorized all six casinos by referendum, and the revenue the casinos generate, if well-managed, could help ease budgetary pressures. Much of it is supposed to be spent on education.

Analysts say MGM’s National Harbor casino, which will have 3,600 slot machines and 140 gaming tables, could be the most lucrative casino on the East Coast. The complex, the length of five football fields, would be topped by an 18-story glass spire encasing 300 hotel suites overlooking the river and, about 10 miles to the north, the Capitol itself — mammon gazing down upon the machinations of mere politicians.

MGM chief James J. Murren insists that at National Harbor the company will put a damper on the usual Las Vegas casino aesthetic, in deference to the serious business conducted across the border in the nation’s capital. The idea, hatched originally by Prince George’s County Executive Rushern L. Baker III and National Harbor developer Milt Peterson, is an undertaking so insistently upscale that it will attract high- rollers from Virginia and the District as well as business types visiting from out of town. Many residents of Prince George’s, the least affluent of the District’s close-in suburbs, would be priced out.

Nonetheless, Prince George’s and Maryland would be the main financial beneficiaries — after MGM itself, of course. By its fifth year in operation, the casino at National Harbor will pay $333 million in state taxes, according to one of several consultants hired by the state. In addition, the project is expected to generate thousands of jobs. We still find much to dislike in a growing dependence on this industry. But if the payoff is as forecast, then Maryland voters may well decide their judgment was correct.