Although they are decried by politicians, almost every candidate receives money from special interest groups. And there are plenty to choose from in Washington - promoting causes and giving to candidates on both the left and the right.
You're probably familiar with many of the big ones...the National Rifle Association, the Teachers Unions, the Chamber of Commerce, the Sierra Club. And although some skew more liberal or conservative, many give even-handedly to the campaigns of elected officials on both sides of the aisle.
So just what does the spectrum of special interest groups on K street look like? To find out, we mapped some of the most powerful advocacy organizations in the beltway along the Crowdpac spectrum using FEC contribution data going back to 1980.
According to Crowdpac's algorithm, Citizens United, which became widely known after winning a landmark Supreme Court decision on corporate political spending, ranks as the furthest to the right ideologically. It's flanked by the Associated Builders and Contractors and the National Auto Dealer Association - both with scores higher than 5 C.
Expectedly, labor unions such as the SEIU, IBEW, and Plumbers & Pipefitters, dominate the liberal end of the spectrum along with abortion rights group EMILY's List.
Some of Washington's biggest players however are at the center of the spectrum, with the National Association of Realtors and the National Beer Wholesalers Association giving to politicians of all stripes.
Now, thanks to Crowdpac, you can create your own PAC. Visit our Act on Issues tool and support the candidates who champion the issues you care about.