The issue of why the Allies did not act on early reports of atrocities in the Auschwitz concentration camp by destroying it or its railways by air during World War II has been a subject of controversy since the late 1970s. Brought to public attention by a 1978 article from historian David Wyman, it has been described by Michael Berenbaum as "a moral question emblematic of the Allied response to the plight of the Jews during the Holocaust", and whether or not the Allies had the requisite knowledge and the technical capability to act continues to be explored by historians.

Background Allied intelligence on the Holocaust

In 1942, Lieutenant Jan Karski reported to the Polish, British and U.S. governments on the situation in occupied Poland, especially the liquidation of the Warsaw Ghetto and the general systematic extermination of the Poles and Jews nationally. He did not know about the murder by gas, repeating the common belief at the time that deported Jews were being exterminated with electricity. Karski met with the Polish government-in-exile, including the Prime Minister, Władysław Sikorski, as well as with members of political parties such as the Socialist Party, National Party, Labor Party, People's Party, Jewish Labour Bund and Zionist Party. He also spoke to Anthony Eden, the British Foreign Secretary, and included a detailed statement on what he had seen in Warsaw and in Bełżec. In 1943 in London he met the author and journalist Arthur Koestler. He then traveled to the United States and reported to President Franklin D. Roosevelt. FDR reacted to Karski's report by inquiring jokingly into animal rights abuses (specifically, horses). His report was a major source of information for the Allies.Władysław Bartoszewski (January 27, 2005), Address by the former Foreign Minister of Poland at the ceremony of the 60th anniversary of the liberation of the concentration camp at Auschwitz-Birkenau. InternationalePolitik.de, pp. 156–157 in PDF.

Karski met also with many other government and civic leaders in the United States, including Felix Frankfurter, Cordell Hull, William Joseph Donovan, and Stephen Wise. Karski presented his report to media, to bishops of various denominations (including Cardinal Samuel Stritch), to members of the Hollywood film industry and artists, but without success. Many of those he spoke to did not believe him, or judged his testimony much exaggerated or saw it as propaganda from the Polish government in exile.E. Thomas Wood and Stanislaw M. Jankowski (1994), Believing the Unbelievable, Karski: How One Man Tried to Stop the Holocaust

In 1942, members of the Polish government in exile launched an official protest against systematic murders of Poles and Jews in occupied Poland, based on Karski's report. The Poles addressed their protest to the 26 Allies who had signed the Declaration by United Nations on January 1, 1942.Engel (2014)

In response, the Allied Powers issued an official statement on December 17, 1942, condemning the known German atrocities. The statement was read to the British House of Commons in a debate led by the Foreign Secretary Anthony Eden, and published on the front page of The New York Times and by many other newspapers such as The Times."Barbarity to Jews: Retribution by Allies: Commons endorse a pledge". The Times, December 18, 1942. At the end of the debate the House of Commons stood for a minute in silence."JEWS (GERMAN BARBARITIES) United Nations Declaration". Hansard, HC Deb 17 December 1942 vol 385 cc. 2082–87. Accessed September 13, 2019. Eden commented that:

On December 13, 1942, the Chief Rabbi of the United Kingdom Joseph Hertz ordained a day of mourning to mark the suffering of "the numberless victims of the Satanic carnage". The Archbishop of Canterbury, William Temple, wrote a letter to The Times to condemn "a horror beyond what imagination can grasp". These responses were mentioned in BBC Radio broadcasts to Europe in several languages that were made on December 17."On This Day, 17 December 1942: Britain condemns massacre of Jews". BBC News. Accessed December 15, 2022.

In 1942, Szmul Zygielbojm, a Jewish-Polish socialist politician, leader of the General Jewish Labor Bund in Poland, and member of the National Council of the Polish government in exile, wrote in English a booklet titled Stop Them Now. German Mass Murder of Jews in Poland, with a foreword by Lord Wedgwood.Szmul Zygielbojm (1942), "Stop Them Now. German Mass Murder of Jews in Poland", London: Liberty Publications.

From April 19, 1943, through April 30, 1943, during the Warsaw Ghetto Uprising of April 19 to May 16, representatives of the governments of the United Kingdom and the United States held an international conference at Hamilton, Bermuda. They discussed the question of Jewish refugees who had been liberated by Allied forces and of those who still remained in German-occupied Europe. The only agreement made was that the war against the Nazis must be won. The US did not raise its immigration quotas. A week later, the American Zionist Committee for a Jewish Army ran an advertisement in The New York Times condemning the United States efforts at Bermuda as a mockery of past promises to the Jewish people and of Jewish suffering under German Nazi occupation."To 5,000,000 Jews in the Nazi Death-Trap Bermuda was a Cruel Mockery", The New York Times, May 4, 1943, p. 17. Szmul Zygielbojm, a member of the Jewish advisory body to the Polish government-in-exile, committed suicide in protest.

Allied intelligence on Auschwitz-Birkenau

From April 1942 to February 1943, British Intelligence intercepted and decoded radio messages sent by the German Order Police, which included daily prisoner returns and death tolls for ten concentration camps, including Auschwitz.

The United States Office of Strategic Services (the predecessor of the Central Intelligence Agency (CIA) and which had been established in 1941–1942 to coordinate intelligence and espionage activities in enemy territory) received reports about Auschwitz during 1942.

Auschwitz prisoners reports The Polish underground reports At the beginning of Operation Reinhard, the principal source of intelligence for the Western Allies about the existence of Auschwitz was the Witold's Report, forwarded via the Polish resistance to the British government in London. It was written by the Polish Army Captain Witold Pilecki who spent a total of 945 days at the camp – the only known person to volunteer to be imprisoned at Auschwitz. He forwarded his report about the camp to Polish resistance headquarters in Warsaw through the underground network known as Związek Organizacji Wojskowej which he organized inside Auschwitz.Jozef Garlinski, Fighting Auschwitz: the Resistance Movement in the Concentration Camp, Fawcett, 1975, , reprinted by Time Life Education, 1993. Pilecki hoped that either the Allies would drop weapons for the Armia Krajowa (AK) to organize an assault on the camp from the outside, or bring in the Polish 1st Independent Parachute Brigade troops to liberate it. A spectacular escape took place on June 20, 1942, when Kazimierz Piechowski (prisoner no. 918) organized a daring passing through the camp's gate along with three friends and co-conspirators, Stanisław Gustaw Jaster, Józef Lempart and Eugeniusz Bendera.Kazimierz Piechowski, Eugenia Bozena Kodecka-Kaczynska, Michal Ziokowski, Byłem Numerem: swiadectwa z Auschwitz. Wydawn. Siostr Loretanek, hardcover, . The escapees were dressed in stolen uniforms as members of the SS-, fully armed and in an SS staff car. They drove out the main gate in a stolen Steyr 120 with a smuggled first report from Pilecki to Polish resistance. The Germans never recaptured any of them. By 1943 however, Pilecki realized that no rescue plans existed in the West. He escaped from the camp on the night of April 26–27, 1943.

The first written accounts of Auschwitz concentration camp were published in 1940/41 in the Polish underground newspapers ("Poland lives") and .Władysław Bartoszewski, , Zachodnia Agencja Prasowa, Warsaw 1967, Interpress, Warsaw 1970, Świat Książki, Warsaw 2008, . Published also in English in 1968. From 1942 members of the Bureau of Information and Propaganda of the Warsaw Area Home Army also began to publish short booklets based on the experiences of escapees. The first was the fictional Auschwitz: Memories of a Prisoner written by Halina Krahelska and published in April 1942 in Warsaw.Halina Krahelska, , BIP Okręgu Warszawskiego AK (Bureau of Information and Propaganda of Warsaw Area Home Army), Warsaw 1942. The second publication was also produced in 1942 in the PPS WRN book ("Camp of Death") written by Natalia Zarembina.Natalia Zarembina, , Wydawnictwo WRN, Warsaw 1942. In the summer of 1942 a book about Auschwitz titled ("In Hell") was written by the Polish writer, social activist and founder of Żegota, Zofia Kossak-SzczuckaZofia Kossak-Szczucka, , Front Odrodzenia Polski, Warszawa 1942.

Polish reports about Auschwitz were also published in English versions. A booklet titled Zarembina was translated into English and published by the Polish Labor Group in New York in March 1944 with the title "Oswiecim, Camp of Death (Underground Report)" with a foreword by Florence Jaffray Harriman. In this report from 1942, the gassing of prisoners was described."Oswiecim, Camp of Death (Underground Report)"

Auschwitz site plans, originating from the Polish government, were passed on to the British Foreign Office on August 18, 1944. Władysław Bartoszewski, himself a former Auschwitz inmate (camp number 4427), said in a speech: "The Polish resistance movement kept informing and alerting the free world to the situation. In the last quarter of 1942, thanks to the Polish emissary Jan Karski and his mission, and also by other means, the Governments of the United Kingdom and of the United States were well informed about what was going on in Auschwitz-Birkenau."Address by the former Foreign Minister of Poland Wladysław Bartoszewski at the ceremony of the 60th anniversary of the liberation of the concentration camp at Auschwitz-Birkenau, 27 January 2005 see pp. 156–157

The Jewish escapees' reports On April 7, 1944, two young Jewish inmates, Rudolf Vrba and Alfréd Wetzler, had escaped from the Auschwitz camp with detailed information about the camp's geography, the gas chambers, and the numbers being killed. The information, later called the Vrba-Wetzler report, is believed to have reached the Jewish community in Budapest by April 27. Roswell McClelland, the U.S. War Refugee Board representative in Switzerland, is known to have received a copy by mid-June, and sent it to the board's executive director on June 16, according to Raul Hilberg.Hilberg, Raul. The Destruction of the European Jews, Yale University Press, 2003, p. 1215. Information based on the report was broadcast on June 15 by the BBC and on June 20 by The New York Times. The full report was first published on November 25, 1944, by the U.S. War Refugee Board, the same day that the last 13 prisoners, all women, were killed in Auschwitz (the women were —killed immediately—leaving open whether they were gassed or otherwise killed).Czech, Danuta (ed.). , Reinbek bei Hamburg, 1989, pp.920 and 933, using information from a series called , and cited in Karny, Miroslav. "The Vrba and Wetzler report", in Berenbaum, Michael & Gutman, Yisrael (eds.). Anatomy of the Auschwitz Death Camp, p. 564, Indiana University Press and the United States Holocaust Memorial Museum, 1994.

Allied reconnaissance and bombing missions

Auschwitz was first overflown by an Allied reconnaissance aircraft on April 4, 1944, in a mission to photograph the synthetic oil plant at Monowitz forced labor camp (Auschwitz III).Gilbert, Martin (January 27, 2005). "Could Britain have done more to stop the horrors of Auschwitz?" The Times. Accessed December 15, 2022.