Dan Gilbert is positioned to be a player in the emerging Internet gambling market, but a state constitutional amendment that he championed might make it hard for him to capitalize on the trend in Ohio. The unique 2009 amendment physically restricts casino gambling to parcels occupied by Gilbert’s Horseshoe casinos in Cleveland and Cincinnati and the Hollywood casinos that Penn National Gaming operates in Columbus and Toledo. Matthew Schuler, executive director of the Ohio Casino Control Commission, goes to conferences and hears regulators from other states openly wonder whether the amendment would prohibit online betting. Christy Prince, an attorney who...