The canceled rally marked the third time in less than a month that Mr. Trump’s re-election campaign has failed to relaunch as planned, as it attempts to restart rallies in the coronavirus era but faces anxiety about group gatherings from its own die-hard supporters.
After the debacle in Tulsa, where Brad Parscale, the campaign manager, had bragged about one million ticket requests only to be surprised by an arena that was more than half empty, the campaign has sought to temper expectations for its follow-up attempts at staging an old-fashioned Trump rally.
The campaign last month canceled a planned rally in Mobile, Ala., where the president was expected to campaign for Tommy Tuberville in his Senate runoff on Tuesday against Jeff Sessions.
As it planned for Portsmouth, there had been no bragging about requests for tickets. There was no showy construction of an overflow stage. Instead, campaign officials were conceding that they could be embarrassed a second time, if it turned out that Trump supporters were too anxious about gathering in a crowded public place to take in a speech they could alternatively watch on television.
The news out of Tulsa also did not make those supporters who were planning to stay home look overly cautious. Tulsa County reported 206 new confirmed cases of the coronavirus on Tuesday and 261 — a record high — on Monday, and Dr. Bruce Dart, the director of the Tulsa Health Department, said at a news conference that it was reasonable to link the spike to the rally and related events.
Maggie Haberman and Jonathan Martin contributed reporting.