The owner of Rosecroft Raceway in Fort Washington is expected to be the biggest opponent of a Maryland ballot question that would allow a casino in Prince George's County, according to state lawmakers.

Maryland voters in November must approve a plan that would authorize a casino in Prince George's and allow table games such as blackjack and roulette.

Despite a provision ensuring Rosecroft will have a chance to compete with developers at National Harbor to bid on the Prince George's casino license, the racetrack's owner, Penn National Gaming, will be the biggest opponent of the plan to expand gambling -- because Penn also owns Hollywood Casino at Charles Town Races in W.Va., according to state Senate President Thomas V. Mike Miller Jr., D-Calvert and Prince George's.

"It's going to be hand-to-hand combat in terms of whether or not the people in Maryland continue to go to West Virginia or they keep the money at home," Miller said.

Penn National spokesman Eric Schippers told lawmakers in Annapolis that the company is concerned the bidding process may not be competitive at all -- plans at National Harbor, where developers have promised to invest $800 million in a casino with MGM Resorts International, have the support of Prince George's County Executive Rushern Baker.

A resort casino at National Harbor "virtually assures the destruction of racing at Rosecroft," Schippers said, and could torpedo the company's investments at other nearby casinos.

Penn National reported a 30 percent dip in revenue at its Cecil County casino when a slots parlor opened in Anne Arundel County this summer. The effect of a Prince George's casino could be worse for the Perryville casino, as well as the West Virginia site, Alan Woinski, editor of Gaming USA Corp., wrote in his industry newsletter.

Officials for Penn National did not return calls for comment.

The company has run campaigns over gambling ballot initiatives before -- it defeated a 2008 effort in Ohio to open a casino in Wilmington by spending $37.9 million to drum up votes against the plan, according to the National Institute on Money in State Politics.

And Penn National spent more money lobbying recently in Maryland than any other company, with $877,432.84 reported to the Maryland State Ethics Commission.

"These ads you see about Romney and Barack Obama, they are going to be dwarfed in the Washington media market between MGM and Penn National," Miller said. "It's going to be a television war."