Organizers initially planned to hold the event at the town’s civic center, which can accommodate about 4,000 people. But after overwhelming interest — the Trump campaign says it has distributed more than 35,000 tickets so far — the rally was relocated to the 43,000-seat Ladd-Peebles Stadium. If it’s jarring to imagine Trump in a setting akin to a Billy Graham crusade, well, that’s just one more way in which the 2016 campaign is confounding conventional political wisdom.

Ever since a mid-July Washington Post poll confirmed that Trump is the leading candidate among white evangelical Republicans (20 percent supported him at the time, compared to 14, 12 and 11 ...