In his article on corruption the Mexican political system Morris begins by saying that corruption has always been a part of the Mexican government tot he point where the two have become synonymous. Morris also hypothesizes that the longstanding negative public reaction to the government, as well as cyclical presence of anti corruption campaigns show that corruption coincides with political stability and that the causes of corruption have not changed much over time. What has changed is the kind of corruption that ensues. As external pressures have increased the stabilizing effect of corruption has changed.
Good summary. Could be a bit more specific.