Outside groups are spending big as the race for an open Wisconsin Senate seat shows signs of tightening.
Independent groups have poured nearly $8.8 million into the race so far, ranking it third nationwide behind the presidential race and a Texas Senate race, based on a tally by the nonpartisan Center for Responsive Politics.
A new poll released Wednesday shows that Democrat Tammy Baldwin appeared to have closed the gap on Republican former Gov. Tommy Thompson.
The poll by Quinnipiac University shows both Baldwin and Thompson with 47 percent support. Thompson had led 50 percent to 40 percent in the last poll done a month ago.
The poll of 1,485 likely voters conducted Sept. 11 through Monday has a margin of error of plus or minus 2.5 percentage points.