I think to a certain extent these things, particularly bumper stickers, are means of personal expression rather than means to actually effect the outcome of an election, but to me the bottom line is, and I know you asked for evidence and I don’t have any, but the people who run campaigns are incredibly savvy, they have a lot of resources, PR firms, focus groups, market research, psychological and demographic research and profiles and if this crap didn’t work they would do it, they wouldn’t put the money into it. Everyone complains about mudslinging and negative campaign ads but if they weren’t effective and productive and beneficial, i.e. if people, the electorate, didn’t respond to them on some level, the campaigns, the candidates wouldn’t put the money into them.