A casino spokeswoman said late Friday that the plaintiffs have agreed not to comment on the lawsuit. Calls to Blagojevich's lead attorney rang unanswered early Saturday.
The action comes after the U.S. Supreme Court decided Monday to stay out of the casinos' fight. The high court let stand without comment a state Supreme Court decision that upheld the law last year.
The renewal of the law in 2008 figures in the federal corruption case against Blagojevich. FBI wiretaps showed an alleged effort by the then-governor to shake down Johnston for a sizable campaign contribution while the bill was pending.
A lawyer for Johnston has said the contribution wasn't made.
Four secretly recorded conversations about the issue were played at Blagojevich's impeachment trial in the state Senate. Blagojevich was arrested in his home Dec. 9 and impeached and removed from office the next month.
Until Friday's lawsuit, the former governor's legal problems had played no role in the dispute over the law's constitutionality.
Now, the casinos claim they were "directly victimized" by Blagojevich's alleged criminal conduct. They want a constructive trust put in place over the $89.2 million they've paid into the fund for the horse racing owners. Their suit also seeks unspecified damages, attorney fees and costs.
