Sen. Ron Johnson (R-Wis.) is getting an early lift from Americans for Prosperity. (Photo by Chip Somodevilla/Getty Images)

The conservative advocacy group Americans for Prosperity is rolling out a three-week, $1.1 million campaign in support of Sen. Ron Johnson (R-Wis.), part of an early effort by the Koch-backed group to build a firewall around Senate Republicans.

The campaign, which launches Wednesday, stresses Johnson’s business credentials over his time in Washington. It includes a gauzy television spot that opens with scenes of the bucolic Wisconsin countryside and a beaming baby, while a female narrator calls the state “a place of inspiration and aspiration.”

“All we ask for is the opportunity to succeed, and Sen. Ron Johnson has the vision to get us there,” she continues. The commercial goes on to praise Johnson as “a businessman who knows how to balance a budget, how to create jobs.”

The ad is set to run on broadcast, cable and digital. It will be bolstered on the ground by a door-knocking effort in seven cities including La Crosse, Waukesha and Milwaukee, where AFP staff and volunteers will hand out a leaflet highlighting the national debt. “The politicians are failing us,” the door hanger reads. “But Ron Johnson was a manufacturer for 30 years.”

“This effort continues our long-term model of holding lawmakers accountable when they go the wrong way, and thanking those who do the right thing,” Luke Hilgemann, AFP's chief executive, said in a statement. “That model has proven successful over the years in Wisconsin, where our volunteers have pressed for historic reforms in spending, taxes, education, and worker freedom; all economic freedom issues that are powering a renaissance for the state. Through it all, Senator Johnson has been a consistent ally of economic freedom. His business background informs his policy decisions, and has helped steel him against special interests.”

The pro-Johnson effort comes as the Koch brothers’ political network and other big-money players are scrambling to insulate congressional Republicans from potential fallout if Donald Trump is at the top of the GOP ticket. In Ohio, the Freedom Partners Action Fund, a super PAC financed by Charles Koch and other conservative donors, is running a TV spot attacking Democratic candidate and former governor Ted Strickland for tax increases during his administration. Another allied group, Concerned Veterans for America, has taken the lead in running ads praising Sen. Patrick J. Toomey of Pennsylvania and Rep. Joseph J. Heck, a Republican seeking to replace Sen. Harry M. Reid, the chamber’s Democratic leader, in Nevada.

But the activities of the Koch-backed groups could also provide fodder for Democrats, who have sought to cast the candidates they support as beholden to the interests of the billionaire industrialists.

On Monday, the campaign of former senator Russell Feingold, who is challenging Johnson, seized on the new AFP ad. “Rather than actually face the people he is supposed to represent, Senator Johnson is content to let billionaires and corporate interests speak on his behalf,” said spokesman Michael Tyler.

Johnson spokesman Brian Reisinger noted that Feingold has been backed by outside groups himself.

“Like a typical career politician, Senator Feingold is saying one thing and doing another,” he said. “Not only has he broken the campaign finance promises he had made to the people of Wisconsin — he’s been letting far-left dark money groups from Washington D.C. do his dirty work since 2013.”