It's opening night for slot-machine gambling in Maryland. You slide a shiny silver dollar into the nearest machine. Lights flash. The noise of clanking coins fills the room. Your heart skips a beat as the tumblers slow to a stop.

Darn -- close, but not this time. Your dollar is gone. But, alas, where did it go?

As he takes office this week as Maryland's 60th governor, Robert L. Ehrlich Jr. confronts the same question. Ehrlich won praise from some and votes from many with his promise to solve Maryland's budgetary woes by legalizing slots. As governor, he must now deliver. But slots may prove to be longer on risks and shorter on payouts than the new governor anticipates.

Gambling in America has exploded during the past two decades. Where once bettors had to trek long distances to Las Vegas or Atlantic City for legal betting action, today each of the 48 continental states either offers some form of legalized, non-lottery gambling or has at least one neighboring state that does.

Gambling proponents in Maryland say the state's resistance to slots has sent millions of dollars in potential revenue to nearby states that offer gambling, including Delaware, West Virginia and New Jersey. When budgets tighten and citizens want neither to pay more taxes nor forgo crucial services, gambling revenue becomes difficult to resist.

The core tension Ehrlich will need to resolve is how best to split slots revenue between investors and the state. Like any other budgetary question, the debate over slots revenue is a zero-sum, divide-the-dollar game that Ehrlich must play carefully.

The more the new governor reserves for Maryland -- Ehrlich has proposed 50 percent from sites to be authorized at four state racetracks -- the more attractive slots become for legislators and voters. If the state keeps too much of the revenue, however, investor incentives to build the infrastructure and take the capital risks will diminish.

And keep your eyes on those in Maryland with a financial stake in slots. Maryland Jockey Club President Joseph DeFrancis and his sister, Karin, recently sold their majority interests in the Pimlico and Laurel racetracks but wrote into their contracts a share of the slots receipts either track earns during the next two decades. As The Post's Craig Whitlock has reported, the Maryland Horse Breeders Association and the Maryland Thoroughbred Horsemen's Association are already grumbling about how slots might affect their livelihoods. Maryland also has a highly developed bingo industry that would be threatened by legalized slots.

Meanwhile, as a political compromise, Ehrlich may be forced to commit some of the state's share of slots revenue to "local impact" programs demanded by state legislators who will complain about the adverse social consequences of gambling. Interest groups opposed to gambling will be all too happy to supply legislators with data demonstrating the deleterious effects of gambling.

Revenue-sharing dilemmas, investor conflicts and social effects will be further exacerbated if, in the end, slots fail to generate the $800 million in annual state revenue the new governor estimates. If a stagnant economy reduces receipts or if the state's cut of those receipts is too small, deficit reduction will be slower than promised. Initial delays in authorizing slots and building the infrastructure at the racetracks would also delay fiscal windfalls.

Ehrlich will first have to pass his slots proposal through the General Assembly, an especially daunting task in the House of Delegates, led by a new, more liberal speaker, Michael E. Busch, who is wary of slots. Despite Ehrlich's 16-year career as a state and national legislator, no significant law carries his name; his unproven legislative skills will be tested immediately.

Ehrlich built his campaign around three main themes. The first was a promise to end what the Republicans claim is a Democratic "culture of corruption" in Annapolis. The second was reducing traffic congestion by pledging to build an intercounty connector linking Interstates 95 and 270. The third was fiscal responsibility, including slots as a budgetary panacea.

Well, if statehouse corruption remains an issue in 2006, it will cut against, not for, Ehrlich, whose recent exploits with a borrowed helicopter undermine his rhetoric of propriety. The intercounty connector is unlikely to be completed by 2006, and, even if it is begun, Ehrlich can gain no political mileage from promising to build a road already under construction.

That leaves slots. If deficits persist in Maryland after slots -- and, should whispers prove true, casino gambling -- are legalized, opponents will call Ehrlich's gambit a failure.

Candidate Ehrlich boasted throughout the campaign that he had won 13 consecutive elections. With his 14th victory, he becomes Maryland's first Republican governor in more than 30 years. But campaign success is no proxy for governing ability, and until today Ehrlich has never led any government, at any level, at any time. Should his gamble on slots fail to pay off, Ehrlich's beloved electoral streak may go the way of your shiny silver dollar.