Three new ballot-issue committees have emerged in the closing weeks of Maryland’s costly fight over expanded gambling, channeling another $2.2 million into attempts to sway voters to support Question 7.

The efforts of the newcomers are narrower than those of the two main committees, which largely have been funded by gambling companies with a big stake in the outcome. MGM Resorts has now given close to $30 million to advocate passage of the measure, while Penn National Gaming has ponied up more than $41 million to oppose it.

The newest committee to register is called the Republican Leaders Referendum Guide. The only funding reported by the group is $271,515 from the Peterson Cos., the developer of National Harbor.

Question 7 would allow a new casino in Prince George’s County, and National Harbor is considered the most likely site. Peterson also has contributed $1.7 million to the committee backed by MGM, which is angling to build the casino at Peterson’s development.

Besides advocating for Question 7, the Republican Leaders committee also has registered to campaign for defeat of some other high-profile measures on Tuesday’s ballot in Maryland: same-sex marriage, in-state tuition for undocumented students and the state’s new congressional map.

Marc DeLeo, director of marketing for the Hollywood Casino at Perryville, left, and John Sanchez, vice president of operations, right, look over slot machines at the casino in Perryville, Md. Maryland's first casino opened ahead of schedule on Monday, Sept. 27, 2010. (Rob Carr/AP)

Literature distributed by the group features pictures of former lieutenant governor Michael Steele and activist and politician Audrey Scott, two well-known Maryland Republicans whose endorsements of Question 7 were touted a couple of weeks ago by the MGM-funded ballot-issue committee, known as For Maryland Jobs and Schools.

Angela Sweeney, a spokeswoman for the Peterson Cos., said Steele and Scott have been “very helpful in getting out our positive message that voting for Question 7 is not only good for Prince George’s County but also good for the entire state.”

The new campaign committee “provides a way for us to support the efforts of these Republican leaders,” Sweeney said.

She said that the Peterson Cos. does not have any official positions on the other ballot measures besides Question 7.

Another new ballot committee is advocating for passage of Question 7, as well as all the other statewide measures confronting Maryland voters. That group, called Forward Maryland, has been sending out direct mail and plans to hand out literature to voters at the polls. Its treasurer is Isaac Salazar, a former Maryland Democratic Party staffer.

Forward Maryland has reported raising $1 million, all of it from donors with a stake in the state’s expanded gambling measure.

The largest contribution is from For Maryland Jobs and Schools, the MGM-funded committee, which has given $650,000.

Another $250,000 has come from a group that includes Caesars Entertainment, which plans to open a casino in downtown Baltimore in 2014. Besides authorizing a new casino, Question 7 also would allow table games, such as black jack and roulette, at Maryland’s five previously designated slots sites, including Baltimore. The same group also has given $4.6 million to the MGM-led committee.

Willard Hackerman, the president and chief executive of Whiting-Turner Contracting Co., has contributed $100,000 to Forward Maryland. Caesars announced in September that it had picked Whiting-Turner to build its casino.

Another relative newcomer to the gambling fight is a ballot-issue committee led by former Prince George’s county executive Wayne K. Curry. His committee, which has received previous media coverage, has raised nearly $1 million for what Curry has described as grass-roots efforts to build support for a Prince George’s casino.

The Peterson Cos. has kicked in $700,000 to Curry’s committee. Gaylord Entertainment, which owns the largest hotel at National Harbor, has given $250,000.

In the past week, a labor union also has registered to make independent expenditures in the gambling fight. UNITE Here, which bills itself as the largest union of gaming workers in the world, reports having spent more than $50,000 advocating for Question 7.