State Senate President Emil Jones summoned more than 30 representatives of Illinois casinos and horse racing tracks to his Springfield office Thursday to tell them that a legislative push to massively expand gambling stands little chance of passing without them getting behind the effort, sources familiar with the gathering said.

Jones (D-Chicago) and Sen. Denny Jacobs (D-East Moline), an architect of riverboat gambling in Illinois, told casino and track lobbyists and executives, including Arlington Park’s Richard L. Duchossois, they “expected everybody to get on board,” a source said. Jones also stressed it was important to keep Chicago and the south suburbs in the gaming mix.

But even if the casino-horse rivalry that has contributed to the death of past gambling bills ends, the current legislation still appears on shaky ground. As more details emerged Thursday, it became clear there will be plenty of things for opponents to attack in the bill, which is designed to raise $1.8 billion for the cash-strapped state.