Political and Judicial Checks on Corruption: Evidence from American State Governments. James E. Alt, March 2008, Paper. "This paper investigates the effects of checks and balances on corruption. Within a presidential system, effective separation of powers is achieved under a divided government, with the executive and legislative branches being controlled by different political parties. When government is unified, no effective separation exists even within a presidential system, but, we argue, can be partially restored by having an accountable judiciary..."