Maryland casino referendum officially the most expensive campaign in state history

And there are four weeks remaining before the Nov. 6 election.

In a filing posted Tuesday with the State Board of Elections, the ballot committee financed by Penn National Gaming reported that its contributions to defeat Question 7 reached $21.6 million — $18 million of which has been spent.

Meanwhile, a pro-expansion committee reported that it has spent $17.7 million. Of that, $14.4 million was supplied by MGM Resorts International with the rest coming from Caesars Entertainment Corp. and the Peterson Companies.

The combined spending of $35.7 million exceeds the $34 million spent by Democrat Martin O’Malley and Republican Robert L. Ehrlich Jr. when O’Malley ousted the incumbent governor.

Passage of Question 7 would allow a casino to be built in suburban Prince George’s County and other casinos in the state to add table games. MGM Resorts wants to build a $700 million hotel-casino in the National Harbor complex, which was developed by the Peterson Companies. Penn National, which operates as casino in neighboring West Virginia, is opposed to the expansion.

The casino company money has financed an advertising war on television, radio and through direct mail. Recent polling has shown passage of Question 7 either trailing the anti-gaming expansion votes or slightly behind.