Introduction

Thousands of protesters rallied at the Michigan Capitol in Lansing, Mich., during the spring of 2012 to oppose Gov. Rick Snyder’s policies. Al Goldis/AP

Membership in labor unions fell last year to its lowest level in nearly a century, but Big Labor remains a major player in national politics.

Labor Day this year is celebrated on the heels of a massive strike by fast-food restaurants workers and a renewed discussion about the merits of raising the minimum wage in the United States. And unions have been vocally supporting a push for comprehensive immigration reform.

In the electoral arena, labor unions have long donated to candidates and urged their members to support like-minded politicians. But during the 2012 election cycle, labor unions represented seven of the top 25 super donors to super PACs, according to research by the Center for Public Integrity.

The United Auto Workers ranked seventh among the biggest super PAC donors, contributing $11.8 million, while the National Education Association ranked eighth and gave $10.8 million.

Other big union-givers included:

It’s worth noting, however, that these seven labor unions collectively gave super PACs about half as much money as billionaire casino magnate Sheldon Adelson and his wife Miriam Adelson, who ranked as the top super PAC donors.