He urged legislators to work with him on its shortcomings, although the bill's House sponsor said his attempts to meet with Quinn have been rebuffed. Rep. Lou Lang, D-Skokie, predicted there would be enough House votes this fall to override Quinn's veto.
At a suburban Chicago appearance late Tuesday morning, Quinn rejected that forecast.
"That veto will be sustained," he told reporters. "I think I did the right thing."
Supporters of the bill estimated the expansion could have brought in up to $1 billion a year, boost tourism and create 100,000 jobs for the state. Chicago Mayor Rahm Emanuel supported the establishment of a city casino. Opponents meanwhile warned of market saturation and raised concerns about the social costs.
The proposal would have established a city-owned Chicago casino with spots for 4,000 people to gamble at once. It also would have added riverboat casinos in Danville, Park City, Rockford and an undecided location in Chicago's south suburbs. Each riverboat casino would have had 1,600 gambling positions and allowed Illinois' 10 existing casinos to grow.
Quinn, who isn't opposed to gambling on principle, had said all along that he wanted a bill with stronger ethical protections. That includes barring the gambling industry from making political contributions. He said the proposal has "too many defects" for him to consider using his amendatory veto powers to change it.
"It's one thing if you had to make some technical changes here and there," Quinn said Tuesday. "This bill just falls way short of what the people of Illinois need when it comes to ethics in government."
In his veto message, Quinn took aim at the proposed Chicago casino, claiming the bill would have allowed it to play by different rules. He said the Illinois Gaming Board wouldn't have the same regulatory authority over the Chicago outlet as it holds over other casinos in the state and that the city casino would not have to follow the state's procurement code in handing out contracts.
That would leave taxpayer-financed contracts "vulnerable to organized crime, unsavory influence and potentially overpriced vendors," Quinn wrote.
In earlier responses to the governor's critique, lawmakers offered follow-up legislation to address some of the concerns. However that wouldn't be considered unless the initial law is signed, and Quinn has said he'd rather get all the legislation signed at once.
Lang said he would seek an override in the fall legislative session and dismissed the suggestion that Quinn might be open to discussing differences with the legislation's authors.
"The bottom line is he doesn't want to sign a gaming bill," Lang said. "If he had language to propose, he would have proposed it."
Quinn also criticized the legislation for providing too little support for public education. Past gambling expansions have been designed to bring in more revenue for public services such as schools, but the 1991 law that created riverboat casinos was intended to help economically depressed cities.