Catholic sisters called “Nuns on the Bus” are hitting the road again this coming week, this time to speak out against the role of big money in elections.

The nuns have gone on similar tours over the past few years to draw attention to income inequality and immigration reform. This year they’re trying to fight the influence of large, undisclosed campaign contributions. They are mobilizing low-income voters ahead of this year’s mid-term elections and will visit 36 cities in 10 key battleground states.