Obviously those with a political ideology will not be swayed by a 30-second spot. However a large number of voters do not educate themselves about the issues and are swayed by these massive ad campaigns.
As for voter ID laws, these are simply modern versions of Jim Crow laws aimed at denying voting rights to minorities and the young. In five years of aggressive prosecutions, the Bush administration convicted a grand total of 86 people for voter fraud. Many were felons and parolees who didn't realize that they were ineligible to vote, not impostors seeking to sway an election.
