The Senate Leadership Fund (SLF) is the principal outside-spending vehicle aligned with Republican leadership in the U.S. Senate. It was established in 2015 by allies of then-Senate Majority Leader Mitch McConnell with the explicit purpose of maintaining and expanding the Republican Senate majority. In every cycle since, it has been among the largest super PACs in the country.
SLF works closely with the affiliated 501(c)(4) “social welfare” organization One Nation, which provided more than $54 million to the super PAC during the 2024 cycle. This dark-money pipeline allows donors who wish to remain anonymous to give to One Nation, which then channels funds to SLF — a structure that critics describe as the central mechanism of modern dark money. SLF spends primarily on independent expenditures in competitive Senate races, including major battleground spending in Ohio and Pennsylvania in 2024.
Website: senateleadershipfund.org · OpenSecrets profile: Senate Leadership Fund