Trump’s plan to force all undocumented immigrants to return home, Johnson said, would be an “economic catastrophe,” because those immigrants own homes and fill jobs American citizens don’t want.

“This is just a direct assault. And when he calls a Hispanic judge a ‘Mexican,’ that is akin to the N-word if you are a U.S.-born Hispanic citizen,” Johnson said, referring to Trump questioning the fairness of a federal judge hearing a lawsuit by former students of the for-profit Trump University.

Johnson and his running mate, former Massachusetts Gov. Bill Weld, are seeking a third-party breakthrough in a year of unusual disillusionment with both major-party candidates.

If voters elect Trump or Democratic nominee Hillary Clinton, Johnson said, political polarization will be “worse than ever.”

The Libertarian ticket, he said, should appeal to a disaffected middle that’s fiscally conservative, socially inclusive, and skeptical of U.S. foreign policy and regime change that doesn’t seem to work.

He said he expects the Libertarian ticket to draw “fifty-fifty” from Republicans and Democrats.

“Trump now has so locked in to the far right, that he has, in my opinion, alienated more than half of Republicans,” Johnson said.