A contrived distinction between 'venal' and 'systematic' corruption
In The Concept of Systematic Corruption in American History (PDF), John Joseph Wallis distinguishes "venal" corruption from "systematic" corruption: the former is motivated by personal gain, while the latter is intended to control the government by "[m]anipulating the economic for political ends." In Wallis's view, venal corruption is relatively harmless from a political perspective, particularly when compared to systematic corruption. Wallis blames politicians for systematic corruption, and exonerates business: "Systematic corruption occurs when politics corrupts economics.... Venal corruption occurs when economics corrupts politics."
Wallis claims that venal corruption will always exist, but he posits that systematic corruption has been eliminated in the U.S.:
"[U]nlimited free entry and competition unrestricted by governments... developed as a solution to systematic corruption: a solution to the political problem of preventing narrow political groups from obtaining uncontested control of governments.... Eliminating systematic corruption required an economic solution to a political problem. Between the 1790s and 1840s, the United States developed a constitutional structure of state governments that mandated free economic entry and competition. It took seventy years, but the round of American state constitutional changes in the 1840s are the heart of what eliminated of [sic] systematic corruption. American governments were so successful at eliminating systematic corruption that we no longer understand what the term corruption meant in the 1800s, nor do we worry about systematic corruption in our political system."
Unfortunately, I do not share Wallis's unbridled optimism about the demise of corruption in our political system. Nor do I believe his distinction between venal and systematic corruption makes any sense in the current political/economic climate. Corruption for personal gain and corruption to amass political power are synonymous: whoever amasses political power via corruption will ultimately use it for personal gain. Corruption is corruption, regardless of whether it is perpetrated by an individual or by individuals on behalf of an institution.
 Wallis, John Joseph, University of Maryland & National Bureau of Economic Research, April, 2005, http://www.gvpt.umd.edu/apworkshop/wallis05.pdf