Now Playing: 5-13-13 Marketplace

Today begins our series "Beyond payday loans," a investigation in collaboration with Propublica that focuses on installment loans, a kind of loan that can trap borrowers in a cycle of debt for years. In Washington, D.C., 501(c)4 nonprofit groups are increasingly partisan lobbying machines on both the left and right. Who can get this tax-exempt status and what are the boundaries for political activism? Also, we track the life of a soybean -- sort of. A Supreme Court ruling protect Monsanto, which controls 90 percent of the expanding soybean production in the U.S. and Latin America.