CPI:

Senate Minority Leader Harry Reid lambasted secret political cash when he appeared last week in a video filmed and produced by a liberal advocacy group.

“Working families can’t compete with billionaires,” Reid, a Nevada Democrat, said in the ad that also featured another liberal luminary in Sen. Elizabeth Warren, D-Mass. “Let’s stop the flood of dark money into our political system and do it now.”

One catch: The group behind the video, a nonprofit called American Family Voices, doesn’t generally reveal who funds its operations — although a Center for Public Integrity review of Internal Revenue Service and Department of Labor records indicates large unions, environmental interests and a major corporate retail lobbying group have this decade provided it with six- or seven-figure contributions.