Money is apparently a very bad thing.
Of course, campaign finance reformers argue that money doesn't equate with speech at all. Money is a uniquely corrupting influence that draws politicos from the straight and narrow like schoolkids to a crack dealer. The next thing you know, they're selling their votes for another fix. Arguing that money isn't part of speech is as sensible as arguing that paper, or ink, or broadcast facilities aren't speech. In political campaigns, you're one voice in opposition to an incumbent candidate who enjoys free mail on the taxpayers' dime, name recognition and guaranteed access to the media.