A new poll from Marquette University shows Democrat Tammy Baldwin back ahead of Republican Tommy Thompson in Wisconsin's U.S. Senate race.

There have been a lot of changes in the Marquette poll over the last two months, as to who's leading the Senate contest. Two weeks ago, it was former Gov. Thompson up by one point. Now, Congresswoman Baldwin leads 47 to 43 percent, according to a survey of 1,200 likely voters between last Thursday and Sunday.  Marquette Pollster Charles Franklin says more voters who identify themselves as independents seem to be going Baldwin's way, "Those pesky independents are shifting again."

But Franklin says Baldwin only holds a one-point lead over Thompson, among people who say they follow politics closely, meaning Democrats need especially strong turnout among casual voters. Franklin says also notable in the Senate race is that perhaps due to heavy negative advertising, both Senate candidates have higher unfavorable numbers than favorable, "When campaigns choose to be negative somebody still has to win."

The poll shows both candidates have a favorable rating of 38 percent, but Thompson's unfavorable is at 51 percent, while Baldwin is at 45. The margin of error in the Marquette poll is about three percent.