Crimea's referendum to leave Ukraine: how did we get here?

 Why is Crimea a flashpoint?
Recent events: how did Crimea get here?
Seizure of Crimea's parliament and the referendum
What next for Crimea?

Why is Crimea a flashpoint?

Crimea is at the centre of one of the biggest geopolitical crises in Europe since the end of the Cold War, as Russia faces off with the west over Ukraine. Crimea is a hub for pro-Russian sentiment, owing to ties with the country which date back centuries. Crimea remains an important base for Russia, both strategically and ideologically, but not all Crimeans are sympathetic to their former ruler – including the historically anti-Russian Crimean Tatars.

 For more on Crimea's unique relationship to Russia, click here.

This week, pro-Moscow authorities have begun preparations for a referendum on the status of Crimea, to be held this Sunday, 16 March. The campaign for annexation of Crimea began as tensions over Ukraine's recent tumult rapidly mounted.

Crimea and Kiev today are ideologically and geographically a long way apart. The referendum, instigated by the peninsula's regional government, was a direct response to the uprisings in Kiev which led to the ouster of a pro-Russian leader in favor of an anti-Russian interim government. In recent weeks, after pro-Russian groups seized government buildings in Crimea, Crimean MPs voted to join Russia. Sunday's referendum will serve to "confirm" that decision.

 For more on Ukraine's crisis and how it reached this stage, click here.

Recent events: how did Crimea get here?

 Pro- and anti-Russian rallies: on 22 February, Ukraine's parliament sided with Kiev's tenacious protesters and voted president Viktor Yanukovych out of office, after four months of civil unrest and political deadlock between demonstrators and Yanukovych's government. The Ukrainian legislature quickly reassembled an interim government as the pro-Russian leader disappeared.

Only days before Yanukovich's ouster, Russia announced surprise military maneuvers, which it then set in motion along the border and in the Black Sea. Immediately after the change in leadership in Kiev, pro-Russian rallies mushroomed in eastern Ukraine, especially in Crimea.

But the east is not uniformly pro-Russian. For instance, in Simferopol, Crimea's regional capital, 10,000 Crimean Tatars shouted "Ukraine is not Russia" before clashing with pro-Russians.

Seizing buildings, hoisting flags: On 27 February, armed men seized government buildings including the regional parliament, putting Russian flags on barricades as they progressed.

Over the next two days, gunmen described as "local ethnic Russian 'self-defense squads'" stormed major airports, including a military-civilian facility in Sevastopol. The murky nature of the seizures – seemingly both methodical and lawless – was amplified when the Russian Night Wolves biker gang, which has close ties to the Kremlin, arrived to guard the latter.

Pro-Russian forces, in unmarked uniforms and equipped with Russian vehicles and weapons, then moved onto the peninsula en masse, surrounding Ukrainian bases and taking up positions in major cities.

The Kremlin steps in: Russian propaganda and mixed local sentiment fuelled continued (and continuing) confusion, as outrage against western "fascists" mingled with discomfort at the Russian occupation. Though genuine pro-Russian sentiment and deep divisionsexist in eastern Ukraine, suspicions persist that Russia has bribed crowds (and violent gangs) – a tactic frequently used by the Kremlin to curb domestic dissent.

Meanwhile, Russia's parliament approved military intervention, though President Vladimir Putin insists Russian troops are neither acting illegally or in Crimea at all. The standoff with Ukrainian military has become increasingly tense, with warning shots fired and a truck smashed through a base's gate.

Seizure of Crimea's parliament and the referendum

Out with the old, in with the new: After gunmen seized the Crimean parliament on 27 February, it quickly began ousting government chiefs and installing new ones including a new regional prime minister, Sergei Aksyonov, whose alleged ties to Ukraine's criminal underworld have bestowed him the moniker "the Goblin".

With gunmen still camped in and around the building, the regional government decided "the only possible way out of the situation … is applying the principles of direct rule", in accordance with the "underlying principles of democracy".

For example: to counter Kiev's vote to hold elections for a new government on 25 May, Simferopol voted to hold a regional referendum deciding Crimea's future on the same day. Aksyonov subsequently announced himself in charge of all Crimea's military and police and appealed for help from Putin.

Then, in a surprisingly brazen move, the Crimean parliament declared the peninsula a territory of Russia. The referendum would therefore would be moved to 16 March, and would serve only to confirm parliament's vote.

International fallout: Ukraine's interim prime minister, Arseniy Yatseniuk, dismissed the vote and referendum as "illegal" and said "no one in the civilized world" would recognize the vote. American and European leaders joined the chorus declaring it illegitimate, and threatened sanctions if Russia were to absorb Crimea, directly or indirectly, after the referendum.

But Crimea quickly entered campaign season, with referendum billboards springing up across the region. Most play on the Kremlin propaganda suggesting Kiev is full of fascists:

Crimean leaders, meanwhile, took a jaunt to Moscow, where they were met by crowds and the Kremlin elite. On the peninsula, international observers were kept from entering the region by armed men as pro-Russian crowds forced a United Nations envoy to flee.

Kiev has warned the Crimean parliament that it faces dissolution unless it cancels the referendum, but has also said it will not use its military to stop secession – possibly leaving Ukrainian soldiers in Crimea stranded – a precarious outcome for all parties.

Please tick 'No': The referendum ballot itself, as posted a few days ago to the parliament's website, doesn't exactly give voters an option to say "No". The two choices are:

"Do you support joining Crimea with the Russian Federation as a subject of Russia?"

"Do you support restoration of the 1992 Crimean constitution, and Crimea's status as part of Ukraine?

This second option is somewhat contradictory: the 1992 constitution asserts Crimea is an independent state and not part of Ukraine (reference to autonomy within Ukraine was inserted at a later date). So by "supporting the restoration of the 1992 constitution" voters will actually support enhanced autonomy. No matter what, voters are ticking a box for independence from Ukraine.

What next for Crimea?

It's unclear how the referendum will go – rallies across Crimea have drawn large crowds for both Ukraine and Russia. Though Putin has said Russia is "not considering" annexing Crimea, the Kremlin has supported its right to self-determination and shown no signs of loosening its de facto occupation. On the contrary, pro-Russian forces have grown more aggressive in recent days.

The US and EU have threatened that the referendum will trigger sanctions – but what they can do, and whether they will do anything, is a complicated problem in its own right. Talks with Russia have stalled as the White House played host to Ukraine's interim prime minister Yatsenyuk in DC on Wednesday. The US administration stepped up its criticism of the referendum, in a joint statement by the G7 leaders which insisted the referendum "would have no legal effect", "would have no moral force" and would not be recognised by the international community.

Despite this, Nato is unlikely to react, although it has sent extra fighter planes to Poland and Lithuania and is conducting exercises.