Washington, D.C. -  The U.S. has roughly 140,000 troops in Iraq right now -- American forces bound in their conduct by military law and the chain of command. Among them, often doing similar work, are nearly 20,000 private security contractors. These aren't the civilian workers who drive trucks or deliver the mail, but private soldiers who make more money than troops do and operate under different rules.

Criticism often focuses on allegations that contracting companies overcharge the military and that contractors have stepped outside the rules of combat, don't coordinate operations with the military or each other and are answerable to no one. In recent weeks, tensions between contractors and enlisted troops have flared into ugly incidents.

Outsourcing wartime tasks to private contractors is an integral part of Defense Secretary Donald Rumsfeld's vision of a leaner, more flexible military. But this flexibility comes at a cost -- in the budget and on the battlefield.

Guests:

Martin Smith, Frontline correspondent and producer of Private Warriors, a documentary about private contractors in Iraq

Peter Singer, fellow at the Brookings Institution in Washington, D.C., and author of Corporate Warriors: The Rise of the Private Military Industry

David Price, U.S. Representative from North Carolina and sponsor of the Transparency and Accountability in Security Contracting Act that passed the House in late May

Doug Brooks, president of the International Peace Operations Association

Visit http://www.npr.org/templates/story/story.php?storyId=4712776 to listen to the interview.