Alaska Senate candidate Dan Sullivan (R) is calling on Sen. Mark BegichMark Peter BegichPerez creates advisory team for DNC transition The future of the Arctic 2016’s battle for the Senate: A shifting map MORE (D-Alaska) to join him in a pact to help bar big spending from unregulated outside groups.

The proposed "Alaska Agreement," modeled on the agreement Scott Brown (R-Mass.) and Elizabeth WarrenElizabeth Ann WarrenTrump's SEC may negate investors' ability to fight securities fraud Schatz's ignorance of our Anglo-American legal heritage illustrates problem with government Dems ponder gender politics of 2020 nominee MORE struck in their 2012 Massachusetts Senate battle, would require each candidate to donate half the amount of money spent on TV and radio by an outside group to charity from their campaign account, nullifying its impact and encouraging those groups to stay out of the race. Sullivan's campaign says their attorney is the same one who advised Brown during the negotiations.

"Third party special interest groups with unlimited spending capability have committed tens of millions of dollars to this race, shattering previous records and crowding out Alaskan voices," Sullivan said in a statement released by his campaign. "It should be Alaskans driving the conversation on where this state needs to go and what kind of leadership it will take in the U.S. Senate to get there."

Begich's campaign responded by calling Sullivan a hypocrite because of his support for the Supreme Court case that deregulated outside spending, a sign the plan is likely a non-starter.

"Sullivan again tried to tell Alaskans one thing, but then quickly revealed the truth today — he supports allowing corporations to engage in unlimited spending in our elections," said Begich campaign manager Susanne Fleek-Green in a statement. "If Dan Sullivan makes it out of his competitive primary, it will be a stark contrast between his put-corporations-first position and Senator Begich's support for real campaign finance reform including support of a constitutional amendment throwing out Citizens United."

Outside groups have been spending big in the state: Put Alaska First, a Begich-allied group, and conservative groups including American Crossroads, the Club for Growth and the Koch brothers-backed Americans for Prosperity have all been on the air to bolster their side.

Third-party spending has been relatively even in Alaska, unlike in many others where GOP groups have dominated. Both Sullivan's and Begich's campaigns have groused about the money pouring into the state.

Only outside groups with unlimited capacity would be banned under the terms of the agreement, not ones that face federal fundraising limits like the Democratic Senatorial Campaign Committee or National Republican Senatorial Committee. 

This post was updated at 4:10 p.m.