To highlight their crimes and exact just retribution  

Glenn Greenwald has an extended description of how the Foley scandal is a perfect storm, with all the elements needed to engage the rather slow imagination of the American public:

But for so many reasons -- its relative simplicity, its crystal clarity, the involvement of emotionally-charged issues, the salacious sex aspects -- this Foley scandal circumvents that whole dynamic. People are paying attention on their own. They don't need pundits or journalists to tell them what to think about it because they are able to form deeply held opinions on their own. None of the standard obfuscation tactics used for so long by Bush followers are working here. To the contrary, their attempted use of those tactics is making things much worse for them, because people can see that Bush followers are attempting -- through the use of patently dishonest and corrupt tactics -- to excuse the inexcusable. And seeing that, it gives great credence to all of the accusations voiced over the last five years that this is how the Bush movement operates in every area, because people can now see it for themselves.

This strikes me as just about the most damning critique of democracy I can think of. How is it that this issue can be a surrogate for whether or not we stay in Iraq, what we do about early childhood education, whether we give our citizens the right to challenge their imprisonment? And if this is how Americans make choices about who leads them, how can those choices have any kind of higher political legitimacy?