When Maryland Gov. Martin O’Malley brokered a compromise on slots in 2007, he cast it as a way to move beyond a divisive issue that had paralyzed Annapolis for years.

The debate clearly hasn’t ended.

On Monday, the final scheduled day of the Maryland General Assembly’s annual session, the issue of gambling will be front and center again.

With the fate of hundreds of other bills still hanging in the balance, including several high on the Democratic governor’s agenda, the House of Delegates has scheduled a 9:30 a.m. hearing on the latest plan to emerge from the pro-gambling Senate.

The bill calls for a statewide referendum on adding a sixth Maryland gambling site in Prince George’s County and allowing Las Vegas-style games at all existing slots venues. It rocketed through the Senate on Saturday.

The odds of passage in the House, where leaders huddled on the issue Sunday night, remain unclear. But even if both the bill and the ballot measure it would spawn succeeded, it would hardly put the issue to rest.

The latest Senate legislation leaves some of the most difficult decisions to next year, including how much to compensate other casino owners for the additional competition. And if those issues were not worked out, a Prince George’s facility could not be licensed.

That would set up yet another year of well-paid gambling lobbyists prowling the halls, trying to protect and extend the interests of their clients.

“You’re never done with this,” said Aaron Meisner, a stockbroker who for years led opposition to introducing slots in Maryland. “You’ll probably see the issue come up in a serious way at least every couple of years now. I think this is the new normal.”

The deal that legislators approved in 2007 and that voters ratified in 2008 allowed five slots venues in jurisdictions whose lawmakers were willing to host them.

Senate leaders have argued that this year’s proposed expansion is needed to help Maryland stay competitive with Delaware, West Virginia and Pennsylvania, all of which already have table games in addition to slots.

And, they say, a casino in Prince George’s — most likely at National Harbor — would be the best-positioned to attract gamblers from Northern Virginia and the District.

“This particular site is not so much a win for Prince George’s County as it is for the entire state,” said Senate President Thomas V. Mike Miller Jr. (D-Calvert). “I’m hoping people look at the state as a whole.”

Competing interests of several jurisdictions are expected to factor heavily into what what happens to the legislation in the closing hours of the 90-day session.

Prince George’s County Executive Rushern L. Baker III (D) has been a fixture in Annapolis in recent weeks, lobbying for a “billion-dollar” casino he would like to see at National Harbor, the mixed-use development on the banks of the Potomac River. Under a bill the Senate passed earlier, which included more details on how revenue would be shared, Baker estimated that a casino could bring his county $69 million a year in gambling and other tax revenue.

But even Baker acknowledges that not all delegates from Prince George’s are convinced of the merits of hosting a casino, an idea most in the delegation opposed in 2007. And under the second Senate bill, there’s no guarantee that the terms would be favorable enough to attract the level of investment Baker is seeking.

Many lawmakers from Anne Arundel County, meanwhile, have rallied around the interests of the developer of a casino scheduled to open in June at Arundel Mills mall. Cordish Cos. has argued the addition of a high-end venue in neighboring Prince George’s would unfairly cut into its market, which includes the District and Virginia.

The biggest wild card in the debate may be the votes of Baltimore lawmakers. A Prince George’s casino could also cut into the business of a venue planned for downtown Baltimore.

Both the city’s mayor and the only bidder for the site, Caesars Entertainment, supported the first Senate bill because it guaranteed higher shares of revenue for the casino owner and the city than existing law. But Baltimore delegates have been wary of the measure, and the second Senate bill leaves more to chance.

“If we’re changing the rules of the game, we’ve got to do something to protect the revenues coming to the Baltimore site,” said Del. Curtis S. Anderson (D-Baltimore), the chairman of the city’s delegation.

O’Malley has largely stayed on the sidelines during this year’s debate. But aides say he is taking a more active role now.

“While a gambling expansion was not something the governor planned to push this session, he has always been willing to work with [Prince George’s] on this issue,” said spokesman Rick Abbruzzese. He was quick to add that the governor’s “primary focus” on the final day of the session will be on another unresolved issue: the state budget.