“Nuns on the Bus” vs the Koch brothers. According to RNS This time it’s the Catholic sisters versus the Koch brothers.

The religious News Service writes…That’s one way to look at the upcoming “Nuns on the Bus” tour, which hits the road next week (Sept. 17) for the third time in three years, a monthlong trip though 10 key U.S. Senate battleground states to campaign against the influence of outside money on politics.

Campbell said the tour isn’t aimed at advocating any particular policy or legislative fixes for unregulated campaign contributions. Instead it will focus on voter registration drives and canvassing low-income neighborhoods to rally voters to cast ballots in November.

“We want to say the 100 percent are welcome to the table of dialogue. But leave your money bags outside the door,” she said.

The issue has come to be identified with the wealthy industrialist brothers Charles and David Koch, whose huge contributions to conservative political causes have raised concerns about the role of “dark money” on elections.

The spigot for such undisclosed donations, which can be made by unions as well as corporations, was opened by the controversial 2010 Citizens United Supreme Court decision. That was followed by another 5-4 ruling in April of this year, McCutcheon v. Federal Election Commission.

“It’s all about ‘we the people’ standing up against big money,” said Sister Simone Campbell, who heads Network, a Catholic social justice lobby on Capitol Hill that is organizing more than 75 events in 36 cities along the 5,252-mile route.

“I wasn’t going to do another bus trip this year,” Campbell said. “I thought, twice in a row — do we do a third one?”

But she said the growing role of outside money in elections, with no requirements to disclose how much is donated and by whom, convinced her that another bus trip was necessary, though she will have to raise $400,000 to fund the trip. Campbell said she has collected about $300,000 so far, mainly from Network members and from foundations that promote voter registration and health care reform.

Campbell said the tour isn’t aimed at advocating any particular policy or legislative fixes for unregulated campaign contributions. Instead it will focus on voter registration drives and canvassing low-income neighborhoods to rally voters to cast ballots in November.

“We want to say the 100 percent are welcome to the table of dialogue. But leave your money bags outside the door,” she said.

The sisters will also sit down with business leaders “to hear their perspective and ask about the common good in their perspective.”

Campbell will be accompanied on the bus by different Catholic sisters from each state the bus visits and they will stay at convents where possible.

The tour starts in Des Moines and at a subsequent stop in Davenport, Iowa, the local Catholic bishop, Martin Amos, will present an award to Campbell.

That’s significant because Campbell was one of the American nuns singled out for criticism in April 2012 by a Vatican investigation of a group representing most U.S. sisters, the Leadership Conference of Women Religious.