Up to polling day on 25 October 2026 Donald Trump did not openly endorse Flavio Bolsonaro, The Guardian reports, the White House site shows no new Brazil action since 2025, and the Federal Register from 5 to 25 October has no new US tariff, sanction or visa ban on Brazil, only a routine Commerce trade duty ruling on one product (dissolving pulp) whose provisional duty was already in force since March.
History. In 4 of 5 cases the loudest act from the foreign power came in the last 16 days before the vote; in Nicaragua in 1990 the US trade ban had been in force for years.
Hunch. Trump had not formally endorsed Flávio by polling day on 4 October and only said he was watching very closely (Al Jazeera, 4 Oct 2026).
The US pressure market resolves on White House, State Department and USTR statements, the Federal Register and Donald Trump's own account: YES if between 5 October and 17:00 Brasília time on 25 October Trump or a cabinet member publicly backs Flávio Bolsonaro by name, or a new US tariff, sanction or visa ban on Brazil or its officials is announced. Tariffs already in force, the consular suspension and the remark about watching closely resolve NO; Reuters and BBC News settle it if the official pages are unclear.
We looked for cases where a close final vote between two candidates came while a foreign power that the country depends on openly acted for one side, with official reports, sanctions or words from its leader, and the other side called it meddling. We found five since 1946: in Argentina, Nicaragua, Ukraine, Poland and Colombia. The US was the foreign power four times and Russia once.