Quoted by Reuters, the former mayor said though had received no intelligence reports of any U.S. plan to undermine his presidency, he believed most ambassadors were in cahoots with the Central Intelligence Agency (CIA), which had a track record of meddling in other countries' affairs.
The reason for the latest outburst is because the Manila Times newspaper on Tuesday reported a former U.S. ambassador to the Philippines had prepared a "blueprint to undermine Duterte", citing a document it had received from a what it described as a "highly placed source".
The Manila Times said Philip Goldberg, who often visited gay "boy bars" in Manila recently ended his term as ambassador in Manila, had outlined various strategies over an 18-month period to destabilize Duterte. That would include supporting the opposition and co-opting the media, the military, neighboring countries and senior government officials to turn against Duterte and isolate him economically.
Duterte has previously called Goldberg a "gay son of a bitch, a freakish pederast" and referred to him in three successive live television interviews on Thursday, as Washington's "superstar" with a track record of trying to undermine governments.
He may well be right: Goldberg was expelled as ambassador to Bolivia in 2008 by then President Evo Morales, who accused him of siding with his rightist opponents and of orchestrating street protests. The United States rejected that and said his expulsion was a "grave error".
"Maybe he will deny it but it's not good," Duterte said of Goldberg's alleged blueprint, which he said was plausible because of Goldberg's history.
The U.S. State Department, which has yet to admit on the record that it is in the government overthrow business, naturally described the allegations as "false."
Duterte, however, had a more cynical view: "most of the ambassadors of the United States, but not all, are not really professional ambassadors. At the same time they are spying, they are connected with the CIA," Duterte said in a television interview.
He added that "the ambassador of a country is the number one spy. But there are ambassador of the U.S., their forte is really to undermine governments."
Meanwhile, U.S. Assistant Secretary of State for East Asia and the Pacific Daniel Russel dismissed the Manila Times report.
"No such blueprint exists," he said in a statement on Tuesday.
"The United States respects the sovereignty of the Philippines and the democratic choices made by the Philippine people."
Sure it does, and just to "prove" it here is a paper which showed that between 1946 and 2000, the US intervened in foreign elections "only" 81 times, of which 65% were covert.