Donald Trump "fired up the crazies" in his state when he held a rally in Phoenix last weekend, Arizona Sen. John McCain said in a recent interview. During that appearance (and others last weekend), Trump was joined by the father of Jamiel Shaw, who was killed by an undocumented immigrant.

Trump has tapped into "some anger" in the state over the conditions at the border, McCain told The New Yorker's Ryan Lizza in an article published Thursday.

"It's very bad," the Republican senator said. "This performance with our friend out in Phoenix is very hurtful to me," McCain said. "Because what he did was he fired up the crazies."

Trump's latest polling numbers would seem to suggest that his message is resonating with Republican voters.

McCain, a longtime supporter of comprehensive immigration reform as a member of the Senate's Gang of Eight, noted his battles with the far right, "very extreme element" of his state's party over the years on the issue.