President Bush challenged four sections of the authorization bill. One would have authorized independent review of how the U.S. is using revenues derived from "the oil resources of Iraq"; another would have required negotiations for an agreement by which Iraq would share some of the costs of the American military operations there. The sections in question, "purport to impose requirements that could inhibit the president’s ability to carry out his constitutional obligations...[as commander in chief]," President Bush wrote. In the other bill, he raised concerns about two sections that strengthen legal protections against political interference with the internal watchdog officials within each executive agency.