The fight to save clean water on the Fort Peck Indian Reservation

Native American leaders in Montana believe the Keystone oil pipeline puts them in grave danger - but they are up against powerful business interests

Lance Four Star drives west at 70mph using his knees to work the steering wheel as he watches the Montana senator Jon Tester's Indian Country Facebook town hall on his wife's smartphone, the video starting and stopping as the cellular signal goes in and out on the 40-mile drive from the middle of the Fort Peck Indian Reservation to its border.

There aren't many jobs on this 2m acre reservation in Montana's north-east corner, and Four Star is brushing up on Tester's policy positions before an interview for a job on the Democrat's re-election campaign, which is in its last hundred days. As a US army veteran, Four Star supports Tester's work reforming the Department of Veterans Affairs, but disagrees with Tester on one major issue: