Matthew Yglesias points out at that the Citizens United decision may have some pretty painful consequences to our politics:

Bank of America, for example, dedicates $2.3 billion to marketing in 2008 so it’s clear that they’ve got the budget to mount a $100 million series of scathing attacks on a Senator who pisses them off and basically laugh that off (and note that in 2004 total spending on Senate campaigns was just $400 million).