Question: Who was a candidate for the Libertarian Party's 2012 nomination for President of the United States, that unsuccessfully challenged during his tenure, the fourth-ranking Republican leader in the House?
Sentence (from "Tom Cole"): As of 2015, Cole – a member of the Chickasaw Nation – is one of only two registered Native Americans in Congress (the other being fellow Oklahoman Markwayne Mullin).
Relevant evidence: No