Federal inquiries into allegations that Illinois Gov. Rod Blagojevich traded and sold political favors for personal gain could derail a state law requiring casinos to share their revenue with the horse racing industry, according to a Wall Street Journal report.

A bill that Blagojevich signed into law Dec. 15 requires the state’s four highest-grossing riverboat casinos to give 3% of their revenue to the horse racing industry. The provision is estimated to be worth as much as $30 million a year, and by law is divided 60% for purses and 40% for tracks.

According to the Journal, a federal affidavit includes allegations that the governor pressured horse racing officials for a $100,000 campaign contribution in exchange for his signature on the most recent revenue-sharing legislation. Blagojevich signed the bill six days after he was arrested for allegedly trying to sell President-elect Barack Obama’s U.S. Senate seat.

Revenue at both Thoroughbred and Standardbred tracks have declined since casinos began operating in Illinois in the 1990s. Casinos have argued the reason is because horse racing’s appeal as a sport is fading. After years of lobbying, a law was passed in 2006 that required the casinos to share their revenue, but the racetracks haven’t seen a nickel because of legal challenges. Casinos filed a suit that argued the law violated the state constitution. In June, the Illinois State Supreme Court ruled against the casinos, which intend to file an appeal with the U.S. Supreme Court. Meanwhile, an estimated $80 million collected under the provisions of the 2006 law sits in an escrow account