MADISON, Wis. (AP) -- Two groups that are part of the network run by Kansas billionaire Charles Koch are launching a combined $1.6 million in new attack ads against Democratic Sen. Tammy Baldwin.
The new television and digital ads announced Wednesday come from Concerned Veterans for America and Americans for Prosperity-Wisconsin. Each said they were spending $800,000 a piece on the spots.
That brings the total the groups have spent in the race against Baldwin to more than $6 million.
Baldwin faces Republican state Sen. Leah Vukmir in the election. Vice President Mike Pence is coming to Milwaukee Thursday to host a fundraiser for Vukmir.
The Center for Responsive Politics says more than $19 million has already been spent by outside groups in the Wisconsin Senate race, making it one of the most expensive in the country.
Tammy Baldwin's campaign responded to the Koch brothers spending with this statement:
“The Koch brothers are continuing to attack Tammy Baldwin because they know ALEC national board member Leah Vukmir will do their bidding. Wisconsinites want someone in their corner and they know Tammy Baldwin stands up to these corporate special interests.”