When President Trump sought solace from arguably the most disastrous week of his presidency, he headed toward Arizona — and seemed to have a grand old time. His speech Tuesday in Phoenix was classic Trump: He lambasted the “very dishonest media,” for almost a half hour; he relitigated his Charlottesville responses in petulant detail; he defended Confederate statues as “our history and our heritage.” And, just for fun, he dangled a possible pardon for Joe Arpaio, the hometown authoritarian former sheriff who was convicted of criminal contempt in July.

What better venue for Mr. Trump, praised just the night before as presidential during his Afghanistan speech, to revert to his natural form? Arizona, after all, is the state that effectively made him president, and not merely for the 11 electoral votes it awarded him last November.

The 45th president’s journey from a stunt candidate to a serious force began in Phoenix, on July 11, 2015, less than a month after his escalator-ride announcement in which he spontaneously excoriated Mexican immigrants as “rapists.” His tiny staff found themselves overwhelmed with ticket requests for a rally at a Phoenix hotel and had to book the Phoenix Convention Center on short notice. Something was about to burst forth that nobody full understood at the time — perhaps not even Mr. Trump himself.

A few immigration activists showed up with banners, and were immediately set upon by an angry crowd of rally attendees who had just discovered that a loudmouth with a Queens accent was just the right person to shout their frustrations by proxy. Perhaps not coincidentally, this was one of the first rallies of his campaign to be broadcast live on cable. The rowdiness and near-gladiatorial atmosphere — along with the symbiotic and contradictory dynamic of media-bashing and media glare — made for ratings gold and would persist at Trump rallies through the campaign. But this strange recipe got its first taste-test in Phoenix.