Campaign ads already having an impact in swing states

With four months to go until Election Day, more than $150 million has already been spent on campaign ads in key swing states, and a new poll suggests that spending is already having an impact on voters' views of the campaign.

A new USA Today/Gallup poll of swing state voters finds most of those polled remember seeing campaign ads over the last month. Most voters—70 percent—say the ads have confirmed their views about the candidates.

But roughly one in 12 say the ads have prompted them to change their minds about a candidate. As USA Today's Susan Page notes, that's a small number, but with President Barack Obama and Mitt Romney statistically tied in most polls, that percentage could prove to be crucial heading into November.

So far, Obama's negative ads against Romney appear to be working. Among those polled who say the ads have changed their minds, 76 percent now support Obama compared to just 16 percent who back Romney.

In a memo to reporters, the Romney campaign discounted the impact of Obama's negative ads, noting that Obama's polling numbers haven't changed since his campaign launched a nearly $50 million ad spree last spring.