MADISON, Wis. (AP) — The first television ad designed to bolster Republican Scott Walker's sagging presidential campaign highlights his 2011 struggle with public sector unions, the clash that made him known across the country.

The 60-second ad by the super PAC Unintimidated begins broadcasting in Iowa on Tuesday as part of a $7 million buy that runs until the Feb. 1 caucuses. It is part of more than $16 million the group backing Walker plans to spend in the next six months for ads in South Carolina, New Hampshire, Nevada and other states. The group released the ad online Thursday in advance of its broadcast.

Titled "Fight & Win," it comes as Walker is taking a more aggressive approach and trying to regain ground lost since early polls placed him in the top tier of GOP rivals.

It begins with dramatic footage of screaming protesters who converged on Wisconsin's capital in 2011 when Walker proposed effectively ending collective bargaining for most public workers. His proposal also forced teachers, state employees and other public union members to pay more for health insurance and pension benefits, as part of a plan to plug a roughly $3 billion budget shortfall.

Those protests, which went on for weeks, grew to be as large as 100,000 people. Walker's signing of the law curbing union rights led to the attempt to recall him from office in 2012, which he defeated.

"Time after time Scott Walker fights and wins," a narrator says over soaring music and footage of Walker's presidential launch event in the summer.

The ad also highlights some of Walker's accomplishments as governor.

It refers to Wisconsin having a "billion dollar surplus," which was true in January 2014 but not now. Facing a $2 billion shortfall this year, Walker pushed through deep spending cuts, including a $250 million reduction to the University of Wisconsin. The state actually ended the 2015 budget year, in June, with a surplus of $71 million, according to latest estimates.

The ad points out that Walker signed $2 billion in tax cuts into law during his first term. Those tax cuts contributed to turning the $1 billion surplus into a potential shortfall in less than a year.

The ad also refers to the state's unemployment rate dropping from 7.8 percent the month before he took office to 4.6 percent in June. It doesn't mention that Walker didn't come close to his signature 2010 campaign promise, repeated in the 2012 recall election, that the state would add 250,000 private sector jobs by the end of 2014. Only 129,000 jobs were added.

Wisconsin's private sector job growth during Walker's first term was 5.7 percent, compared with 9.3 percent growth nationwide.

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