The top 7 things we're looking for from the upcoming Tuesday showdown.
A robocall from Karl Rove's Crossroads GPS to voters in Wisconsin focuses on the danger Democrats allegedly pose to seniors on Medicare.
Specifically, the call targets Rep. Tammy Baldwin, who is still ahead in the Senate race, by a narrowing margin, over former governor Tommy Thompson.
"Hi, this is Crossroads GPS with a message about Medicare," a man's voice says.
"Tammy Baldwin voted for ObamaCare, which will cut $9.46 billion in Medicare payments in Wisconsin alone. Medicare Advantage enrollees in Wisconsin could be reduced by 45 percent.
"And, under ObamaCare, 15 unelected bureaucrats could restrict access to medical treatment and care of Wisconsin seniors."
The voice then directs people to call Baldwin at her local Congressional office "and tell her to restore seniors' health care and work for real health-care reform."
"Learn more about the Crossroads GPS New Majority Agenda on health care, and action you can take at www.newmajorityagenda.org," the call concludes.
Crossroads GPS and the New Majority Agenda are among the "dark money" groups pouring millions into ads Wisconsin and other swing states.
Across the nation, these ads have featured similar misleading statements about the Affordable Care Act (ACA)--also known as ObamaCare.
The cuts to Medicare cited in these ads do not include cuts to benefits for seniors, but efforts to make the program more efficient. Politifact has rated claims in a Florida race by the Chamber of Commerce that the ACA would cut benefits for seniors "mostly false" and "pants on fire."
Medicare spending under the ACA will continue to increase, and benefits will not be cut under the law, although the increases in Medicare spending are set to go up at a lower rate over time because of efforts to make the program operate more efficiently, the Kaiser Family Foundation notes.
Another claim--that, under the ACA, a 15-member, unelected board will make decisions "rationing" health care for seniors--has also been debunked by FactCheck.org.
The board in question--known as the Independent Payment Advisory Board--"cannot, by law, 'ration' care or determine which treatments Medicare covers. In fact, the IPAB is limited in what it can do to curb the growth of Medicare spending," FactCheck.org explains.
The section of the ACA that sets up the board specifically declares: "The proposal shall not include any recommendation to ration health care, raise revenues or Medicare beneficiary premiums . . . increase Medicare beneficiary cost-sharing (including deductibles, coinsurance, and copayments), or otherwise restrict benefits or modify eligibility criteria."
What the board can do is seek savings from payments to hospitals and nursing facilities, and through Medicare Advantage, the Part D prescription drug program.
As it happens, Medicare Part D has become an issue in the Wisconsin Senate race.
On the campaign trail in and in her ads, Tammy Baldwin points out that Tommy Thompson helped craft Medicare Part D as "a sweetheart deal for the drug companies"--when he was George W. Bush's Health and Human Services secretary.
In particular, Baldwin bashes Thompson for helping push the provision that makes it illegal for the federal government to negotiate for better prices from the drug companies.
More and more, the race for U.S. Senate in Wisconsin seems to hinge on Medicare, according to a recent article by Dee Hall in the Wisconsin State Journal.
In a speech to a Tea Party group in Oconomowoc, Thompson was caught on tape saying:
“Who better than me, who’s already finished one of the entitlement programs (to) come up with programs to do away with Medicaid and Medicare?”
The Baldwin campaign jumped on that statement.
Thompson's list of top contributors is a directory of large health care companies.
Yet as governor, Thompson implemented ObamaCare-like programs to expand health care coverage for low-income families and drug coverage for seniors in Wisconsin.
Look for more ads and calls by dark money groups like Karl Rove's that muddy the waters on this issue.
If you liked this article by Ruth Conniff, the political editor of The Progressive, check out her story "Tommy/Tammy Senate Debate in Wisconsin."
Follow Ruth Conniff @rconniff on Twitter