For some reason, former South Carolina governor Nikki Haley was a speaker at the Republican convention on Monday night. Nobody is fooled by the unified front that Haley’s appearance presents. Haley was not at the RNC to signal her support for the populist agenda that Donald Trump ran on in 2016, and should run on in 2020 as well. She was there to advance her own ambitions, through superficial association with the Trump administration. These ambitions should be checked now. Allowing Nikki Haley to become a leader in the Republican Party would be a return to Bush-era conservatism, defined by...