The Pentagon's system of outsourcing to private companies the task of moving supplies in Afghanistan, and leaving it up to them to provide their own security, frees U.S. troops to focus on counterinsurgency.But its unintended consequences undermine U.S. efforts to curtail corruption and build an effective Afghan government, according to the report to be reviewed at a congressional hearing on Tuesday."This arrangement has fueled a vast protection racket run by a shadowy network of warlords, strongmen, commanders, corrupt Afghan officials, and perhaps others," Representative John Tierney, chairman of a House of Representatives national security subcommittee, said in a statement.