The elections were held using the absolute majority system, under which a candidate had to receive over 50% of the popular vote to be elected. If no candidate received over 50% of the vote, both houses of the National Congress would come together to vote on the two candidates who received the most votes.[2]
The US was countering the influence of the Soviet Union, who supported Allende with $50,000 to $400,000 every year between 1960 and 1969.[5] In total the CIA spent $3 million in the 1964 elections, more money than Lyndon B. Johnson spent on his 1964 presidential campaign.[6]
^Bevins, Vincent (2020). The Jakarta Method: Washington's Anticommunist Crusade and the Mass Murder Program that Shaped Our World. PublicAffairs. ISBN978-1541742406.