It's not easy to get to the right of U.S. Rep. James Lankford, a staunch conservative from a state that prides itself on being "the reddest of the red."
Yet the 46-year-old rising star in the national GOP now finds himself fighting for political survival in a primary election for a U.S. Senate seat that may show whether the insurgent backlash against Republican incumbents extends into another conservative bastion.
Lankford is being challenged by T.W. Shannon, the former speaker of the Oklahoma House of Representatives. Both are so conservative that local tea party groups aren't sure who to support.
Drawing further attention to the race is Shannon's ethnicity: he was the state's first black House speaker and is also Native American. Leaders of major tribes are backing him financially.
© Copyright 2016 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.