Americans for Prosperity is busing hundreds of out-of-state conservative activists to the country’s most contested political battlegrounds.

This weekend, the powerful nonprofit, founded and funded by billionaire David Koch, is sending 160 Oklahoma activists to help mobilize voters in Colorado. Meanwhile, 180 canvassers from Utah, Idaho, Arizona, Oregon and California will converge on Nevada, another key swing state in the presidential race.

The deployments mark the final stage of a $30 million effort to oust President Barack Obama and Democratic Senators, relying almost exclusively on issue advocacy advertisements, direct mail and other get-out-the-vote efforts.

Two weeks from now, AFP plans to send five busloads of conservatives from New Jersey, New York and Maryland to fortify its ground game in Pennsylvania. The group’s Georgia chapter has a crew of 200 lined up for Florida. Maryland also will send a team of 40 activists to neighboring Virginia during two separate weekend bus-ins. The weekend before the elections, the Arkansas state chapter expects to send two buses to the crucial battleground of Ohio.

Sarah Hill, a 56-year-old accountant traveling with AFP to Colorado Springs, Colo., said she participated in tea party rallies as early as 2009, but had never knocked on doors before.

“It’s just too important not to,” she said. “I’ve never owned a gun until recently either, but we have got to defend our republic.”

Delivering partisans to competitive states in the final weeks of a campaign is hardly a unique strategy, but the extent of AFP’s plan — paired with its other election activities — highlights the new role social welfare nonprofits have adopted during this election cycle. The group played it particularly well this spring, flooding Wisconsin with more than 100 AFP field staffers to help defeat a recall effort aimed at Republican Gov. Scott Walker.

AFP is footing the bill for the trips, including transportation, lodging and an iPad for each activist programmed with an application that leads them from door to door and provides a script unique to each household. The messages are aimed primarily at unseating Obama, as well as vulnerable Democratic Senators.

AFP, a 501(c)(4) tax-exempt organization, has been criticized for abusing its tax status with hard-hitting advertisements, robocalls, direct mail and door knocking operations that seem more like campaign activities than social welfare work.

“[They say] what they have to say to protect the c4 status,” said Frances Hill, who studies income tax, constitutional and election law at the University of Miami. “They are trying to avoid being characterized as a political committee, which has to comply with FEC reporting requirements.”

Because of its nonprofit status, the group does not have to disclose its donors and only has to report expenditures expressly targeting a candidate to the Federal Election Commission.

“All of these efforts are issue advocacy,” Levi Russell, a spokesman for AFP, said in an email. “So volunteers aren’t talking about the election or telling anyone how to vote. They’re delivering a message on why President Obama’s agenda is failing.”

But aboard the bus rumbling toward Colorado, the elections weighed heavy on the minds of volunteers, who planned to hit 10,000 houses this weekend.

“Just think back to Florida. … Some elections are determined by less than 1,000 votes,” Stuart Jolly, AFP’s Oklahoma state director said by phone. “The elections could hinge on these four busses.”