n Obama’s case, it is clear that external events have consumed much of the news agenda over the last eighteen months, including the Deepwater Horizon oil spill, the Arab Spring revolts, the shooting of Rep. Gabrielle Giffords, the earthquake and tsunami in Japan and the killing of Osama bin Laden. The saturation coverage that these stories received left little room for scandal, particularly given the volume of debate over the merits of the president’s legislative agenda and his confrontation with the new Republican majority in the House.

Other, less quantifiable factors seem to have also played an important role. As the first black president, Obama may be treated less harshly by the press than some of his predecessors. In addition, the birther movement diverted a great deal of conservative time and energy into the false claim that Obama was not eligible to hold office, generating a controversy that received a great deal of media attention but which never made the transition into a full-blown scandal.

Going forward, though, the odds of scandal are high and rising. Obama already faces low approval among GOP identifiers and a similarly hostile climate in Congress. Back in March, New York Times columnist Paul Krugman noted that Republicans hadn’t yet made a serious effort to back up claims that the Obama White House is “one of the most corrupt administrations.” As more time passes, pressure to find evidence of misconduct is likely to build — my data suggest that the risk of scandal increases dramatically as the period without a scandal stretches beyond two years.