Experts see contradictions in the [Iranian] version of the downing of the aircraft and suspect that the admission is a result of either a trade-off or pressures on Tehran.
Probably, the Polish deputies decided that with the help of one piece of paper they could change the past and wash off the close military-political union with Hitler. This made the Munich conspiracy to divide Czechoslovakia in 1938 possible, which predetermined the further expansion of the Nazis. So if we talk about the second country which has responsibility for starting Second World War, it is Poland itself.
Historical revisionism consistent with recurring disinformation pro-Kremlin disinformation narrative about Poland and World War II. Poland did not start World War II, it was Nazi Germany, which attacked Poland on 1 September 1939, and Soviet troops entered Polish territory on 17 September. By the early part of 1939, Hitler had become determined to invade and occupy Poland. Secret negotiations between Nazi Germany and the Soviet Union led to the signing of the Molotov-Ribbentrop Pact in Moscow on 23-24 August 1939. In a secret protocol of this pact, the Germans and the Soviets agreed that Poland should be divided between them, with the Western part of the country going to Germany and the eastern two-thirds being taken over by the USSR. Read more here. In September 2019 the European Parliament adopted a resolution on the importance of European remembrance and expressed deep concern regarding the efforts of the current Russian leadership to distort historical facts and whitewash crimes committed by the Soviet totalitarian regime. See previous pro-Kremlin disinformation cases alleging that Poland was the initiator of WWII and that Poland was the organiser of WWII and its main culprit.