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 "R. J. Harris"): Richard Jason Satawk "R. J." Harris (born November 16, 1972) is a United States Army National Guard warrant officer, politician, law student and former Air Traffic Controller.
Relevant evidence: Yes