Mayday PAC, a super PAC trying to curtail the influence of super PACs in politics, endorsed three more congressional candidates on Monday: Rep. Walter Jones (R-N.C.), Rep. Carol Shea-Porter (D-N.H.) and Ruben Gallego, a Democratic candidate in Arizona's 7th district.

Mayday PAC said it now plans to target eight congressional races in the midterm election. Its initial goal was five races.

The group, the brainchild of Harvard law professor Lawrence Lessig and GOP media strategist Mark McKinnon, is trying to reduce the influence of money in politics by helping to elect candidates who have pledged to reform campaign finance laws.

Mayday PAC has already raised more $7.8 million, a surprisingly high number. It's one of several groups that have emerged this year as a force in the campaign finance reform movement.

The group is launching a round of radio ads in the New Hampshire Senate race, where it is backing underdog candidate Jim Rubens (R). One of the ads calls Rubens the only Republican candidate for Senate in the country "who has had the courage" to take on the "cronyism" that defines the current campaign finance landscape.

Mayday PAC also backs Democrat Staci Appel in Iowa's 3rd district race.