I just finished Al Gore's book Assault on Reason and he has some harsh things to say about marketing.
One of his points is that candidates can buy votes by simply purchasing 30 second ads. He recounts a story about when he was running for a senate position and his adviser told him that if he invested X amount into 30 second ads he would see an X amount increase in his polls, and he was exactly right. Gore goes on to criticize the ability of advertising to shape public opinion.
Furthermore he suggests that marketing's influence is harmful to the marketplace because it can increase demand artificially, instead of allowing the invisible hand of supply and demand to balance on its own.
I agree that marketing has great power to persuade, but it is not to blame for citizens not doing research to be informed on issues. I blame that on people being lazy. The book cites a study that found people who thought Arnold Schwarzenegger and George W. Bush were on the Supreme Court. Secondly I disagree that increasing demand for products through marketing is harmful, because branding actually increases the value of products. However, I really liked this book and would highly recommend it.