Iran also continues to be fodder for both campaigns.
Thompson's latest ad, in addition to talking about 9/11 and body armor, also criticized Baldwin for taking $60,000 in campaign donations from a group that opposes sanctions against Iran and for voting four times against Iranian sanctions. Since entering the Senate race, Baldwin has voted twice in favor of expanding sanctions.
Baldwin last week ran an ad attacking Thompson for investing in seven companies that have ties with Iran, including one that partnered with the country to mine for uranium. Thompson said he sold stocks, worth about $38,000, from all those companies.
On Monday, Wisconsin Democratic Party chairman Mike Tate called on Thompson to resign from all corporate boards before the election.
Tate questioned whether corporate interests were attempting to buy the Senate seat for Thompson, a former U.S. health secretary who joined a number of private health company boards after leaving his government post in 2005.
Tate pointed to Thompson's disclosure on a filing with the Securities and Exchange Commission that showed that on Oct. 1 he took ownership of 1,200 shares of stock in C.R. Bard Inc., worth $126,000. The New Jersey company last year paid $184 million to resolve 2,600 lawsuits, but still has about 1,000 others pending.
Thompson had previously reported that C.R. Bard paid him $1.2 million from 2005 through 2010. His compensation included thousands of dollars in stock awards each year he did work for the company.
Thompson turned questions at a news conference about the payment into an attack on Democrats.
"It's sad in our society the Democrats have nothing credible to offer these days," he said. "They have no plans to attack America's problems. The problems facing America are not stock that I own in C.R. Bard."
Associated Press writer Carrie Antlfinger contributed to this report from Milwaukee.