Another huge one! So much more than this! Starting point:
most USSR leaders got there by becoming the head of the Soviet Union’s Communist Party.
Vladimir Lenin 1922-1924 founded the Russian Communist Party consequently becoming 1st Soviet head of state.
There's been strikes and uprisings going on since 1905. Serfs had had enough, country poorly run. Come WW1, following the February Revolution, Czar Nicolas abdicates, brother Michael refuses the crown. A temporary government trys to keep things working.
Lenin - leader of the Bolshevik revolutionary party, exiled in Switzerland, legs it back (across the German lines) to help lead the October Revolution that brings a new Soviet government. Russian Empire ends 1917,
The revolution sparks Russian Civil War. Lenin’s Red Army win. In 1922 a treaty is signed with Ukraine, Belarus and Transcaucasia ( includes Armenia, Azerbaijan and Georgia) to form the Soviet Union, or USSR.
(later becomes 15 republics of 130 ethnic groups over 11 time zones, guaranteed rights of national territories, native-language schools and cultural organizations but socialist values and practices.)
That year, Lenin's health starts failing A bullet stuck in his neck since 1918 was removed but he went downhill, then a fatal stroke in Jan, 1924, age 53.
He'd wanted workers and peasants to have political power and rights, but hadn't achieved it when he died.
Joseph Stalin 1924-1953 was in the 1917 October Revolution and in 1922 he became secretary general of the Communist Party’s Central Committee (held till he died 1953)
Lenin disliked Stalin trying unsuccessfully to remove him. Most thought Leon Trotsky, also part of the October Revolution would take over from Lenin.
Stalin disliked Trotsky, and Stalin, Zinovyev, Kamenev took over together..
In1920s, Stalin pushed Zinovyev and Kamenev out, created a dictatorship and exiled Trotsky. In the 1930s, he started the Great Purge, and killed off rivals.. Zinovyev and Kamenev, put through a show trial, tortured into false confessions and shot. In 1936, an absent Trotsky was sentenced to death, and in 1940 was living in and killed in Mexico City, with an ice pick in the head by a Soviet agent.
WW2 an alliance of sorts formed with U.S. (Roosevelt) and U.K. (Churchill) and Soviet troops helped liberate Nazi concentration camps. The spoils and displaced people's fate were decided on at the Yalta Agreement in 1947. Goes awry, starting a cold war against USSR. March 1953, Stalin dies from brain hemorrhage.
Georgy Malenkov 1953-1953 took over the next day. He'd helped Stalin with the Great Purge. But a few weeks later Nikita Khrushchev who'd joined the CP in 1918, politically outmaneuvered Malenkov sliding himself and allies into key positions and creating a new structure: the five-man Secretariat.
Although he held 'titles' Malenkov had no actual power by the end of the year. In 1955, Khruschev officially became president.
Nikita Khrushchev 1953-1964 became 1st secretary of the CP (actually more powerful) and, in 1958, its leader.
He sought de-Stalinization and better international relations. But when the CIA tried to overthrow Cuba's Fidel Castro, and the Cuban Missile Crisis, US and SU came close to nuclear war. He and Kennedy actually both pulled back but in 1964, Leonid Brezhnev and his allies pushed him out.
Leonid Brezhnev 1964-1982 was 10 in 1917, joined the CP youth as a teen and was a soldier in WWII.
He was 2nd secretary when Khrushchev was pushed out and became 1st secretary and SU leader. (In '66 1st sec was changed to general secretary).
Brezhnev led detente from '67 to '79 easing the Cold War creating better trade with Us, and US allies. But brought in policy that USSR should intervene wherever socialist or communist rule was threatened, leading to SU Afghan invasion in '79 ending détente. Brezhnev had a fatal heart attack in Nov. '82.
You then get Yuri Andropov 1982-1984 head of the KGB '67 to '82. left KGB to become general secretary 2 days after Brezhnev died. Strained relationship with Reagan. 1983 kidneys started failing, dies '84.
So you get Konstantin Chernenko 1984-1985 who'd failed to succeed Brezhnev in '82. He had emphysema and died a year later.
Leading to Mikhail Gorbachev, who brought in perestroika and glasnost but was struggling to change and hold a modern SU together.
Yeltsin on the rise in the background wanted dissolution, and won high popularity in '89, and resigned from the CP. Yeltsin fought against a military coup against Gorbachev but started dismantling the CP. All the (by now 15) SU republics made grabs for independence. Gorbachev resigned Xmas day (UK) '91.
Yeltsin was a very mixed bag, bringing in Capitalism, and many elements of Neoliberalism, but a lot of previously banned freedoms. Drank too much, accepted perks that he'd previously criticized. Survived impeachment, disbanded a mainly communist- parliament in 93 and called for elections, but when it didn't go down well had tanks shell parliament. '94 Yeltsin sent troops in against Chechnya, killing 80,000 mostly civilians. '95-98 several heart attacks and another impeachment attempt, went through several presidents. Ruble collapsed and Russia couldn't pay its bills, but rising oil prices saved it.
New Years eve 1999, Yeltsin unexpectedly resigned asking the people forgiveness for some of his extremes. Handed power to Vladimir Putin, his last prime minister, who granted Yeltsin immunity from prosecution, and headed Russia back to centralization of authority and restriction, and quite possibly a new version of USSR.