The AFL-CIO has it, and they’re threatening to use it if CEO pay goes unchecked. Here’s hoping they follow through:

WASHINGTON — The nation’s largest labor union on Friday threatened to challenge the powerful chairman of the Senate Banking Committee in the 2014 elections, if he allows a key set of new executive pay regulations be weakened.

The surprising remark occurred during a panel discussion moderated by The Huffington Post atSocial Investment Forum Conference. The summit was attended by hundreds of socially conscious investors ranging from religious groups like the Unitarian Church to high-profile investment houses like Mesirow Financial.

During the panel, a top technocrat on the Banking Committee, General Counsel Dean Shahinhian warned that investors may have to accept a weaker-than-anticipated version of new disclosures on CEO pay mandated by last year’s Wall Street reform bill. Shahinian also acknowledged that his boss, committee chairman Sen. Tim Johnson (D-S.D.), would be willing to re-open last year’s landmark legislation and rewrite some aspects of the law if bipartisan political consensus about some measures could be established.

AFL-CIO Special Policy Counsel Damon Silvers immediately interrupted Shahinian: “I think Senator Johnson needs to think about his political future,” he said. The audience of potential campaign contributors let out an audible gasp.

Shahinian responded that Silvers’ comment was “inappropriate” for the panel, but the union lawyer did not apologize.

Instead, he instructed Shahinian to consider “the recent personal history of Blanche Lincoln.” The AFL-CIO is widely credited with ruining any chance the former Democratic senator from Arkansas had of win reelection in 2008. Walmart, the world’s largest retailer is headquartered in Lincoln’s state, and the labor union had repeatedly objected to her positions on key workers’ rights issues.

Unable to win over Lincoln, the AFL-CIO spent millions of dollars supporting progressive Democratic challenger Bill Halter in the 2008 primaries. Halter lost the primary, but the divided Democratic base caused Lincoln to suffer a landslide loss in the general election.

At the Friday panel, Silvers vowed to provide the same treatment to Johnson — one of the most Wall Street-friendly Democrats in the Senate — if he does not make sure that Dodd-Frank remains intact.