A slot machine at the Hollywood Casino in Perryville. (Photo by Doug Kapustin/For The Washington Post)

On Monday, O’Malley plans to meet with Prince George’s County Executive Rushern L. Baker III (D), Montgomery County Executive Isiah Leggett (D) and Baltimore Mayor Stephanie Rawlings-Blake (D).

Baker and Rawlings-Blake have both voiced support for a plan that would allow a Prince George’s County casino — most likely at National Harbor — and allow Las Vegas-style table games at all Maryland slots venues, including one planned in Baltimore. Leggett spoke favorably of a Prince George’s casino during a radio interview last week, saying Baker had made a convincing case.

If an expanded gambling bill has a chance of passing the House of Delegates, the support of members from Prince George’s, Montgomery and Baltimore will be key. O’Malley plans to gauge the commitment of the mayor and two county executives to helping pass a bill, an aide said.

On Tuesday, O’Malley is scheduled to meet with Senate President Thomas V. Mike Miller Jr. (D-Calvert) and House Speaker Michael E. Busch (D-Anne Arundel). Miller is a big supporter of an expanded gambling plan, but Busch has cautioned that the idea remains a tough sell in the House.

Last month, a work group set up by O’Malley stopped short of recommending an expanded gambling plan because three members from the House withheld their support. Five members appointed by O’Malley and three state senators on the 11-member work group backed the plan, which included a Prince George’s casino and some tax relief for existing casinos that would face new competition for gamblers.

One challenge Busch faces in the House is a lack of support from Republicans. On Thursday, the GOP House caucus reaffirmed its opposition to holding a special session on gambling.

“We want to make it clear that our 43-member caucus still adamantly opposes, in the strongest terms possible, any special session on gambling,” said House Minority Leader Anthony J. O’Donnell (R-Calvert). “There is no crisis or emergency demanding an extraordinary special session. The best way to deal with the public policy issue of expanded gambling is through the normal order of the regular legislative session in January.”

O’Malley has said he wants to resolve the issue prior to the November elections. Any major expansion of gambling in Maryland must be put to a public vote after legislative passage.