1. On March 16, over 95% of voters in Crimea backed a plan to secede from Ukraine and join Russia.
2. The referendum followed months of protests that forced out Ukraine’s pro-Kremlin president. Putin is expected to reveal Russia’s plan for Crimea in a speech before a special session of parliament on Tuesday.
3. Now, there is growing unrest in the east of Ukraine, which also has close ties to Russia and counts many Russian speakers among its residents. There is increasing talk of the possibility of a Russian invasion. How did we get here?
4. Back on March 1, one week after former Ukrainian President Viktor Yanukovych fled Kiev, Vladimir Putin announced his intention to send troops to the Crimean peninsula, a semi-autonomous region of Ukraine.
The war powers that Putin got from Russia’s upper house of parliament extended to all of Ukraine. The day before, Crimea saw the rise of a new provincial government that refused to accept the new government in Kiev.
5. Russian officials repeatedly argued the need to defend Russian speakers in Crimea and the rest of Ukraine from anti-Russia attacks. Many Ukrainians condemned the move as an “invasion” and dismissed claims of attacks.
6. Many in predominately Russian-speaking Crimea identify strongly with Russia. Crimea houses Russia’s Black Sea fleet, making it both of symbolic and military importance for Russia.
The majority of Crimeans are ethnically Russian, retaining strong cultural, familial, linguistic, and political ties to Moscow. Soviet Russia gave Ukraine the region of Crimea in 1954, which Ukraine then retained after the Soviet Union fell apart in 1991, counter to Russian opposition.
7. Troops with no identifiable markings, who first appeared days before in Crimea, increased their street presence. Putin and others denied the official presence of Russian troops and called the soldiers local “self-defense” units.
8. These unmarked soldiers — who Ukraine claimed were sent by Russia — now had control over key government buildings and the airport in Crimea.
9. By March 2, an estimated 16,000 Russian troops were in Crimea, surrounding Ukrainian military bases. Ukraine ordered its armed forces on full alert and said Russia had “effectively declared war.”
10. Western condemnation poured in, with the U.S. and EU threatening political and economic sanctions against Russia for effectively annexing Crimea in violation of international agreements.
11. On March 3, the White House offered $1 billion in aid to support Ukraine’s interim government to hold fair elections, implement economic reform, combat corruption, and withstand “politically motivated trade actions by Russia.”
Russia often uses its vast gas resources — the Russian gas giant Gazprom supplies controls nearly one-fifth of the world’s gas reserves — as political leverage in the region. Russia supplies Ukraine with more than half of its gas annually, while around 80% of the gas Russia exports to Europe first passes through Ukraine. Russia repeatedly fought “gas wars” with Ukraine, threatening to cut subsidies to maintain power in Ukraine’s political future.
12. The next day, Putin gave his first remarks on Ukraine since ordering troops into Crimea. In a defiant speech from Moscow, he affirmed the Kremlin’s right to use all options in Ukraine, but adding “there is no reason yet” to use military force.
13. Secretary of State John Kerry arrived in Kiev the same day to meet with Ukraine’s interim government. He reiterated support for a diplomatic solution and condemned Russia’s “act of aggression.”
14. On March 6, Obama announced an expected set of sanctions against Russia, including visa bans and an executive order against Russian officials “who are most directly involved in destabilizing Ukraine.”
15. The threats did little to deter Russia. Most in Crimea supported a return to Russian control. But Crimea’s minority Muslim population, the Tatars, came out against Russia’s intervention.
16. As the referendum neared, violent clashes broke out across the east, where ties to Russia are strongest. In Odessa, Donetsk, and Kharkiv, pro-Russia crowds captured administrative buildings and called for autonomy from Kiev.
17. On March 13, protests in Donetsk turned deadly. Some claimed pro-Russian activists had provoked the violence, in hopes of bolstering Russia’s claim that it needed to intervene in order to protect Russian speakers and return calm.
18. On March 14, Kerry met Russian Foreign Minister Sergei Lavrov in London. The talks did not go well.
19. Lavrov said after the meeting that Russia had no plans to “invade” Ukraine. The Russian Foreign Ministry also issued a statement that same day saying Russia “reserved the right” to protect its “countrymen” in Ukraine.
20. With ever more talk of war, tens of thousands of Muscovites rallied against Russia’s intervention in Ukraine. It was the largest anti-Putin protest in two years. In east Ukraine, another two pro-Ukrainian activists died as clashes escalated.
21. On March 17, Obama issued a new executive order imposing fresh sanctions and visa bans on 11 Russians and Ukrainians, including seven high-ranking Russian government officials, for their role in the Crimea referendum and Ukraine escalation.
A White House official called them the most “comprehensive” sanctions on Russia since the end of the Cold War. The European Union also put sanctions on 21 officials involved with Crimea’s breakaway efforts.