Rich Lowry: Trump is the GOP Mainstream

The showdown between President Donald Trump and Sen. Jeff Flake turned out to be no contest. It wasn't Trump who was out of the GOP mainstream, but Flake.

The Arizona senator supported Gang of Eight-style immigration reform, when immigration restriction is becoming a litmus-test issue in the party. He is a Goldwaterite, libertarian-inflected conservative, when the market for libertarianism within the party is limited and diminishing by the day.

He is frankly anti-Trump, when Trump owns the party. Many Republican voters are fully aware of the president's flaws, but they don't want to hear about...