Maryland Gov. Martin O’Malley. (Brian Witte/AP)

“I’d still like to find a way to resolve this,” O’Malley said during an interview in Williamsburg, Va., where he is attending a conference of the National Governors Association. O’Malley said the odds of moving forward this summer remain about “50-50.”

O’Malley has been scrambling in recent weeks to salvage a work-group proposal that included both a Prince George’s casino, most likely at National Harbor, and the authorization of Las Vegas-style table games at Maryland’s five existing slots sites.

The plan was shelved last month after three members from the House of Delegates withheld their support. Five O’Malley appointees and three senators on the work group were all on board.

As part of a continuing effort to craft a plan that could win support in the House, O’Malley said Friday that he is open to the idea of allowing a yet-to-be-formed gaming commission to make adjustments to the tax rates imposed on casino owners.

Since the launch of Maryland’s slots program in 2007, the legislature has been responsible for setting the tax rate, which is currently among the highest in the nation — at 67 percent for most facilities.

The Maryland Live ! Casino opened last month in Anne Arundel County. (Mark Gail/The Washington Post)

A majority of members on the work group recommended lowering the tax rate on some existing casinos to compensate for the additional competition that would come with a new venue in Prince George’s.

The owner of Maryland Live!, a casino that opened last month in neighboring Anne Arundel County, has been particularly vocal about its potential to lose gamblers from the Washington region.

O’Malley said that while some legislators might “jealously guard their prerogative” to set tax rates on casinos, he suspects that more would like to get “out of the business” of doing so.

O’Malley said another outstanding issue is the timing of a Prince George's casino. Some legislators have advocated not allowing one to open for a few years, to give existing venues an opportunity to operate longer under existing rules.

There remains an incentive for the legislature to act soon, however. Any major expansion of gaming in Maryland — including new casinos and the authorization of table games — would require approval of statewide voters after legislative action. Lawmakers would have to act by mid-August for a measure to get on the November ballot. Otherwise, it could not appear until 2014.

The governor had originally advertised a special session on gambling for this week. He is now looking at late this month or early August.

O’Malley has scheduled two key meetings next week that could factor heavily into how he proceeds.

On Monday, he plans to meet with three supporters of an expanded gambling plan: Prince George’s County Executive Rushern L. Baker III (D), Montgomery County Isiah Leggett (D) and Baltimore Mayor Stephanie Rawlings-Blake (D).

O’Malley said their views are important because delegates from each of those three jurisdictions make up “such a large bloc of votes that can affect this issue.”

On Tuesday, O’Malley is scheduled to meet with House Speaker Michael E. Busch (D) and Senate President Thomas V. Mike Miller Jr. (D).

“The legislature is never excited about being called back into special session,” O’Malley said. “We’ll need to make a decision within the next week to 10 days.”