Question: Who led the military organization that assisted in operations in northeastern Yugoslavia, and made it an effective fighting force?

full_context: Document 1: Red Army: In the late 1920s and throughout the 1930s, Soviet military theoreticians led by Marshal Mikhail Tukhachevsky developed the deep operations doctrine, a direct consequence of their Polish - Soviet War and Russian Civil War experiences. To achieve victory, deep operations envisage simultaneous corps - and army - size unit maneuvers of simultaneous parallel attacks throughout the depth of the enemy's ground forces, inducing catastrophic defensive failure. The deep battle doctrine relies upon aviation and armor advances in the hope that maneuver warfare offers quick, efficient, and decisive victory. Marshal Tukhachevsky said that aerial warfare must be ``employed against targets beyond the range of infantry, artillery, and other arms. For maximum tactical effect aircraft should be employed en masse, concentrated in time and space, against targets of the highest tactical importance. ''
Document 2: Battle of Warsaw (1920): The battle of Warsaw was fought from August 12–25, 1920 as Red Army forces commanded by Mikhail Tukhachevsky approached the Polish capital of Warsaw and the nearby Modlin Fortress. On August 16, Polish forces commanded by Józef Piłsudski counterattacked from the south, disrupting the enemy's offensive, forcing the Russian forces into a disorganized withdrawal eastward and behind the Neman River. Estimated Russian losses were 10,000 killed, 500 missing, 30,000 wounded, and 66,000 taken prisoner, compared with Polish losses of some 4,500 killed, 10,000 missing, and 22,000 wounded.
Document 3: The Blitz: In the 1920s and 1930s, air power theorists Giulio Douhet and Billy Mitchell espoused the idea that air forces could win wars by themselves, without a need for land and sea fighting. It was thought there was no defence against air attack, particularly at night. Enemy industry, their seats of government, factories and communications could be destroyed, effectively taking away their means to resist. It was also thought the bombing of residential centres would cause a collapse of civilian will, which might have led to the collapse of production and civil life. Democracies, where the populace was allowed to show overt disapproval of the ruling government, were thought particularly vulnerable. This thinking was prevalent in both the RAF and what was then known as the United States Army Air Corps (USAAC) between the two world wars. RAF Bomber Command's policy in particular would attempt to achieve victory through the destruction of civilian will, communications and industry.
Document 4: Josip Broz Tito: After the Partisans managed to endure and avoid these intense Axis attacks between January and June 1943, and the extent of Chetnik collaboration became evident, Allied leaders switched their support from Draža Mihailović to Tito. King Peter II, American President Franklin Roosevelt and British Prime Minister Winston Churchill joined Soviet Premier Joseph Stalin in officially recognising Tito and the Partisans at the Tehran Conference. This resulted in Allied aid being parachuted behind Axis lines to assist the Partisans. On 17 June 1944 on the Dalmatian island of Vis, the Treaty of Vis (Viški sporazum) was signed in an attempt to merge Tito's government (the AVNOJ) with the government in exile of King Peter II. The Balkan Air Force was formed in June 1944 to control operations that were mainly aimed at aiding his forces.
Document 5: Josip Broz Tito: As the Communist Party was outlawed in Yugoslavia starting on 30 December 1920, Josip Broz took on many assumed names during his activity within the Party, including "Rudi", "Walter", and "Tito." Broz himself explains:
Document 6: The Blitz: British air doctrine, since the time of Chief of the Air Staff Hugh Trenchard in the early 1920s, had stressed offence was the best means of defence. British defensive strategy revolved around offensive action, what became known as the cult of the offensive. To prevent German formations from hitting targets in Britain, RAF's Bomber Command would destroy Luftwaffe aircraft on their own bases, aircraft in their factories and fuel reserves by attacking oil plants. This philosophy was impractical as Bomber Command lacked the technology and equipment and needed several years to develop it. This strategy retarded the development of fighter defences in the 1930s. Dowding agreed air defence would require some offensive action, and fighters could not defend Britain alone. Until September 1940, the RAF lacked specialist night-fighting aircraft and relied on anti-aircraft units which were poorly equipped and lacking in numbers.
Document 7: Josip Broz Tito: On 12 September 1944, King Peter II called on all Yugoslavs to come together under Tito's leadership and stated that those who did not were "traitors", by which time Tito was recognized by all Allied authorities (including the government-in-exile) as the Prime Minister of Yugoslavia, in addition to commander-in-chief of the Yugoslav forces. On 28 September 1944, the Telegraph Agency of the Soviet Union (TASS) reported that Tito signed an agreement with the Soviet Union allowing "temporary entry" of Soviet troops into Yugoslav territory which allowed the Red Army to assist in operations in the northeastern areas of Yugoslavia. With their strategic right flank secured by the Allied advance, the Partisans prepared and executed a massive general offensive which succeeded in breaking through German lines and forcing a retreat beyond Yugoslav borders. After the Partisan victory and the end of hostilities in Europe, all external forces were ordered off Yugoslav territory.
Document 8: Josip Broz Tito: In the first post war years Tito was widely considered a communist leader very loyal to Moscow, indeed, he was often viewed as second only to Stalin in the Eastern Bloc. In fact, Stalin and Tito had an uneasy alliance from the start, with Stalin considering Tito too independent.
Document 9: Josip Broz Tito: Prime Minister Josip Broz Tito met with the president of the Bishops' Conference of Yugoslavia, Aloysius Stepinac on 4 June 1945, two days after his release from imprisonment. The two could not reach an agreement on the state of the Catholic Church. Under Stepinac's leadership, the bishops' conference released a letter condemning alleged Partisan war crimes in September, 1945. The following year Stepinac was arrested and put on trial. In October 1946, in its first special session for 75 years, the Vatican excommunicated Tito and the Yugoslav government for sentencing Stepinac to 16 years in prison on charges of assisting Ustaše terror and of supporting forced conversions of Serbs to Catholicism. Stepinac received preferential treatment in recognition of his status and the sentence was soon shortened and reduced to house-arrest, with the option of emigration open to the archbishop. At the conclusion of the "Informbiro period", reforms rendered Yugoslavia considerably more religiously liberal than the Eastern Bloc states.
Document 10: Kliment Voroshilov tank: The Kliment Voroshilov (KV) tanks, a series of Soviet heavy tanks named after the Soviet defence commissar and politician Kliment Voroshilov, operated with the Red Army during World War II. The KV tanks were known for their heavy armour protection during the early stages of the war, especially during the first year of the German invasion of the Soviet Union. In certain situations, even a single KV-1 or KV-2 supported by infantry could halt large German formations. The German Wehrmacht at that time rarely deployed its tanks against KVs, as their own armament was too poor to deal with the ""Russischer Koloss"" – "Russian Colossus".
Document 11: Josip Broz Tito: He was General Secretary (later Chairman of the Presidium) of the League of Communists of Yugoslavia (1939–80), and went on to lead the World War II Yugoslav guerrilla movement, the Partisans (1941–45). After the war, he was the Prime Minister (1944–63), President (later President for Life) (1953–80) of the Socialist Federal Republic of Yugoslavia (SFRY). From 1943 to his death in 1980, he held the rank of Marshal of Yugoslavia, serving as the supreme commander of the Yugoslav military, the Yugoslav People's Army (JNA). With a highly favourable reputation abroad in both Cold War blocs, Josip Broz Tito received some 98 foreign decorations, including the Legion of Honour and the Order of the Bath.
Document 12: Anti-aircraft warfare: The most extreme case was the Soviet Union, and this model may still be followed in some countries: it was a separate service, on a par with the navy or ground force. In the Soviet Union this was called Voyska PVO, and had both fighter aircraft and ground-based systems. This was divided into two arms, PVO Strany, the Strategic Air defence Service responsible for Air Defence of the Homeland, created in 1941 and becoming an independent service in 1954, and PVO SV, Air Defence of the Ground Forces. Subsequently these became part of the air force and ground forces respectively
Document 13: Josip Broz Tito: Yugoslavia organized the Yugoslav People's Army (Jugoslavenska narodna armija, or JNA) from the Partisan movement and became the fourth strongest army in Europe at the time. The State Security Administration (Uprava državne bezbednosti/sigurnosti/varnosti, UDBA) was also formed as the new secret police, along with a security agency, the Department of People's Security (Organ Zaštite Naroda (Armije), OZNA). Yugoslav intelligence was charged with imprisoning and bringing to trial large numbers of Nazi collaborators; controversially, this included Catholic clergymen due to the widespread involvement of Croatian Catholic clergy with the Ustaša regime. Draža Mihailović was found guilty of collaboration, high treason and war crimes and was subsequently executed by firing squad in July 1946.
Document 14: Josip Broz Tito: He was General Secretary (later Chairman of the Presidium) of the League of Communists of Yugoslavia (1939–1980) and went on to lead the World War II Yugoslav guerrilla movement, the Partisans (1941–1945). After the war, he was the Prime Minister (1944–1963), President (later President for Life) (1953–1980) of the Socialist Federal Republic of Yugoslavia (SFRY). From 1943 to his death in 1980, he held the rank of Marshal of Yugoslavia, serving as the supreme commander of the Yugoslav military, the Yugoslav People's Army (JNA). With a highly favourable reputation abroad in both Cold War blocs, he received some 98 foreign decorations, including the Legion of Honour and the Order of the Bath.
Document 15: Modern history: The Russian Civil War was a multi-party war that occurred within the former Russian Empire after the Russian provisional government collapsed and the Soviets under the domination of the Bolshevik party assumed power, first in Petrograd (St. Petersburg) and then in other places. In the wake of the October Revolution, the old Russian Imperial Army had been demobilized; the volunteer-based Red Guard was the Bolsheviks' main military force, augmented by an armed military component of the Cheka, the Bolshevik state security apparatus. There was an instituted mandatory conscription of the rural peasantry into the Red Army. Opposition of rural Russians to Red Army conscription units was overcome by taking hostages and shooting them when necessary in order to force compliance. Former Tsarist officers were utilized as "military specialists" (voenspetsy), taking their families hostage in order to ensure loyalty. At the start of the war, three-fourths of the Red Army officer corps was composed of former Tsarist officers. By its end, 83% of all Red Army divisional and corps commanders were ex-Tsarist soldiers.
ground_truth: Marshal Mikhail Tukhachevsky
sub_queries: Who assisted in operations in ortheastern areas of Yugoslavia? Answer: Red Army
who led Red Army and made it an effective fighting force Answer: Marshal Mikhail Tukhachevsky