Texas’ U.S. Senate race pits Air Force veteran M.J. Hegar, a Democrat, against the incumbent, Republican John Cornyn. Cornyn has been in office for almost 18 years, and yet a recent University of Texas poll found about a quarter of registered voters were either neutral on his job performance or had no opinion. Each of the nation’s 100 U.S. Senators is a person with substantial power to affect government policy and make choices with very high stakes. So, what has John Cornyn done with that power? Here’s a look at four major areas.