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"): The chairman of the National Republican Congressional Committee (NRCC) from 2006 to 2008, he was, during his tenure, the fourth-ranking Republican leader in the House.
Relevant evidence: Yes