MILWAUKEE (WTAQ) - The latest Marquette Law School shows that Republicans are gaining ground in both the presidential and the U.S. Senate races in Wisconsin – and both are now considered toss-ups.

The Democrats have a razor thin lead in both. But statistically, they’re considered to be tied because both surveys are well within the poll’s 3.4 percent margin of error.

President Obama leads Republican Mitt Romney 49 to 48 percent – and Democrat Tammy Baldwin also leads Republican Tommy Thompson in the Senate race by just one point, 46-45.

The Marquette poll surveyed 870 likely voters between last Thursday and Sunday.

Polling director Charles Franklin said the first presidential debate had a big impact – and Romney was the clear beneficiary. 73 percent of the likely Wisconsin voters surveyed said they watched the first debate. And those who watched gave Romney a two-point edge, while those who didn’t watch it favored Obama by 8 points.

Franklin said the president held a steady lead in September for Wisconsin’s 10 electoral votes – but since the debates began, the Badger State is now a true tossup.

Also, the Marquette poll shows that the effects from the negative TV advertising in the Senate race are canceling each other out.

48 percent agreed with the Democrat’s statement that former Governor Thompson “sold out to special interests and isn’t working for you anymore.” An identical 48 percent agree with Thompson’s ads saying that Baldwin is one of the most liberal members of the U.S. House and is “too liberal for Wisconsin.”