A new San Francisco-based super PAC known as CounterPAC is preparing to spend money on elections–to fight money in elections.

Specifically, CounterPAC plans to run political ads to urge congressional candidates in some of the nation’s most competitive political races to sign a pledge to not accept “dark money”–money from outside groups or funds from unknown sources on their behalf.

In essence, CounterPAC co-founders Jim Greer and Zack Booth Simpson are seeking to have candidates “bilaterally disarm” by signing this pledge. The startup, which presents itself as non-partisan, will begin by targeting races  that are highly-competitive and where the political candidates are well-matched in terms of outside donations.

While the average CounterPAC campaign will cost approximately $150,000 to run, the group is seeking eventually to have candidates in every race for federal office take a pledge to not take money from super PACs.

In 2014, Counter PAC test-drove its model in several competitive races, using its funds to run television, radio and newspaper ads to influence both Republican and Democratic candidates to take a non-super PAC pledge.

The startup is something of a response to the landmark Supreme Court ruling in the Citizens United case in 2010, which permitted corporations and unions to spend on behalf of candidates, and which has been a target of the left ever since.

Among races that are likely on CounterPAC’s radar during this next election cycle are California’s 17th Congressional race between eight-year incumbent Rep. Mike Honda (D-CA) and his fellow Democratic opponent Ro Khanna; and the Arizona race against incumbent Sen. John McCain (R).

Ultimately, CounterPAC hopes the positive results of its initial efforts will bring about tangible legislative change in campaign finance.

As part of the CounterPAC pledge, candidates who sign the group’s petition must give 50 percent of any money spent on their behalf by a group with undisclosed or murky donors to a charity of their opponent’s choosing.

A similar proposal in California by businessman and attorney John Cox is a ballot measure that would require politicians to display the logos of their top ten donors. In order for the initiative to appear on the November ballot, it will require 365,000 signatures by the end of April. It currently has about 10% of that amount.

Follow Adelle Nazarian on Twitter @AdelleNaz.