Cullen's Pulitzer-winning editorials were based on the paper's reporting on nitrate pollution of streams and "prairie pothole" lakes in northwest Iowa, which helped prompt the Des Moines Water Works to sue three area counties for failing to control the pollution. The counties' insurance policies didn't cover such claims, and officials wouldn't reveal how they were going to pay the legal bills, so Cullen got help from the Iowa FOI Council, which demanded the names of donors under threat of a lawsuit. The records were heavily redacted, but showed that the counties had agreed with the Iowa Farm Bureau and the Agribusiness Association of Iowa to keep the donors secret. Cullen said the AAI was subject to the state open-records law because it was acting as an agent for the counties, and the paper knew that representatives of Monsanto Co. and Koch Industries had met with AAI to discuss setting up the defense fund. The paper's investigation provided grist for Cullen's editorials.
Cullen said "a few" readers canceled subscriptions, saying the paper was "anti-farmer," but he said the Des Moines Register poll found that most rural Iowans agreed with the position of the water works, that agricultural fertilizer is primarily responsible for the nitrate pollution. He said the paper's circulation has increased, and "I think people want to see a fighter." He also said accountability journalism and editorial writing "is the future because people want to be told the right way to go."
But to survive, newspapers must use those tools to appeal to younger readers, Cullen said. "All our readers are dying," he said. "We have to figure this out in the next five years or it's goodnight, Irene."