Sponsored by The Center for Responsive Politics, a non-partisan, non-profit research group that tracks money in politics, and its effect on elections and public policy. Provides financial info on politicians, PAC's, 527's, industries, lobbyists, etc. as well as info on private travel, the 'revolving door' and more.
Non-partisan think tank for campaign finance policy. Provides analysis of issues and also provides campaign finance-related tables, including some from Vital Statistics on Congress (see Statistics section of this guide).
From Stanford University. "Contains over 100 million political contributions made by individuals and organizations to local, state, and federal elections spanning a period from 1979 to 2012. A corresponding database of candidates and committees provides additional information on state and federal elections."
From the National Institute on Money in State Politics - 'the only nonpartisan, nonprofit organization revealing the influence of campaign money on state-level elections and public policy in all 50 states.'