A composite image shows part of the NPR/Center for Responsive Politics reporting team's whiteboard at NPR headquarters that was used to map out how Wellspring connects to other social welfare groups. (Click the enlarge button to see a full-size image.) John W. Poole/NPR hide caption

itoggle caption John W. Poole/NPR

The Au Sable River in Michigan is a popular place for fly fishermen and the heart of a debate unexpectedly influenced by largely invisible social welfare organizations. Christine Arrasmith/NPR hide caption

itoggle caption Christine Arrasmith/NPR

The Olmsted Locks and Dam project is under construction on the Ohio River between Illinois and Kentucky. U.S. Army Corps of Engineers hide caption

itoggle caption U.S. Army Corps of Engineers