BRASÍLIA — President Jair Bolsonaro of Brazil called dozens of foreign diplomats to the presidential palace on Monday to tell them that he believed the country’s voting systems could be rigged, a potential preview of his strategy for an election that is 75 days away and that polls forecast he will lose in a landslide.
While Mr. Bolsonaro’s presentation was not new — he has repeated those claims for years — his audience was. He had invited officials from most of the embassies in…