Political corruption isn’t just about under-the-table dealings. A major factor that contributes to a system that many see as broken in the state of Illinois and throughout the country is a culture of patronage that, although obfuscated, is perfectly legal.

Campaign contributions pay for more than a few amenities enjoyed by politicians without breaking any laws. What do the contributors get for their investment?

As Corrupt Illinois co-author Thomas Gradel told WBBM Chicago political editor Craig Dellimore, “The only thing that distinguishes campaign money from out and out bribes, is that it’s legal.”

The real distinction is that political contributors can’t openly ask for favors in return for the generous donations. Yet the unspoken message is often one of quid-pro-quo.

“It’s very obvious when you look at the track record,” Gradel says, citing reporting from the State Journal Register that is quoted in Corrupt Illinois. “40 percent of the people who contributed to the Governor’s campaign in the period they were covering got state contracts.”

Listen to the full interview here: