The Soviet Ambassador Lysenko (excellently played by Joss Ackland) is wearing a red, flag-shaped lapel pin. The President’s National Security Advisor Mr. Pelt (also excellently portrayed by Richard Jordan) is likewise wearing a US flag lapel pin.
However, the ambassador’s pin is not a simple Soviet Union national flag. Upon closer inspection, it appears to be emblazoned with the text “ВЕРХОВНЫЙ СОВЕТ СССР,” “Supreme Soviet of the USSR.” This was the most powerful legislative body in the Soviet Union.
Similar (almost certainly replica) pins can be found for about $15 on Ali Baba, or for ludicrously high prices on eBay.