Last Republican US Senator to Lose a Primary: Richard Lugar, 2012

After Mike Lee defeated Bob Bennett in Utah in 2010 and then Richard Lugar was defeated in 2012, Mitch McConnell was pissed. He thereafter ensured that EVERY Republican incumbent, no matter how awful, was to be protected from removal by fellow Republican. McConnell and the NRSC would choose which Republicans sat in the Senate, not the infernal people. Republican senators could either leave the Senate on their own, or be defeated by a Democrat. Those were the ONLY two options. For fourteen years, in cycle after cycle, not a single Republican incumbent has been defeated in a primary. This month...