Chicago had been steadily losing conventions to the glitz of Las Vegas as well as sunshine and theme parks of Orlando, Fla., even though exhibitors preferred to show their wares in the city of big shoulders.

“They wanted to come to Chicago, because the people will actually look at their exhibits,” said Illinois Senate President John Cullerton.

But Chicago is a union town — to do business here means playing by union rules.

So, an exhibitor needed to pay the teamsters to haul his exhibit to the convention center and the carpenter’s union to set up a booth. If the carpenters worked past 4:30, they went on overtime, even if they started at 3:00.

Now, you need to plug in your booth to make the whole thing work – you need to pay someone else to do that.

“Instead of a few $100 that it might be in other cities that person is literally spending over $1,200 just to have a computer connected to the Internet and have the power for it,” said exhibitor Mathew Cohn. “It’s a very expensive place to do business.”

One by one, the conventions — which drive 66,000 jobs and generate $251 million in tax revenue — fled for Mickey Mouse and the rolling dice.

When two major conventions pulled out, Illinois got nervous.

“We seem to be in trouble, I mean as a city, we seem to be in trouble,” said Jim Reilly of Chicago’s Metropolitan Pier and Exhibition.

So, the Illinois Legislature passed a “Bill of Rights” for exhibitors.

With the legislation, exhibitors can set up their own booths, contract their own electricians and overtime is limited.

The Chicago Regional Council of Carpenters responded with a lawsuit saying they’ve been singled out and pushed to unemployment.

A union lawyer issued a statement saying: “This Legislation will destroy the historic work of the carpenter in the Chicago tradeshow industry and result in the loss of some of the best tradeshow workers in the country, who will be forced to abandon the trade in order to support their families.”

But the bill of rights suddenly made Chicago more “exhibitor friendly” and the exhodus reversed.

Six new customers decided to hold conventions at McCormick Place. The International Home and Housewares Show negotiated a 5-year commitment and the Convention and Tourism Bureau projected a $1 billion windfall.

“We’ve done this to help the unions,” Cullerton Said. “The unions will have more work.”