WASHINGTON -- After a lull in activity, events began moving very quickly in Ukraine over the weekend. Pro-Russian protesters seized a government building in the eastern city of Donetsk, proclaiming an independent republic and vowing to hold a referendum on regional sovereignty by May 11 -- two weeks ahead of Ukraine's presidential election on May 25. Some of the protesters have reportedly called on Russia to send in troops.
The Russian government has said it has no intention of intervening on the Ukrainian mainland but has reserved the right to protect ethnic Russians living there. Ukraine's interim president, Oleksandr Turchynov, has accused Russia of playing out the Crimea scenario: Activists seize power, hold a referendum on independence, Russian troops move in for their protection and the territory is annexed.
Of course, eastern Ukraine is quite different from Crimea -- bigger, less historically autonomous, less overwhelmingly Russian in its demographics. Kyiv and its Western allies have also had more time to prepare than they did prior to the Crimea events, which took place almost in the immediate wake of the overthrow of the Ukrainian government.
In March, Ukraine mobilized tens of thousands of reservists and diverted $600 million toward the purchase of weapons. This is not to say Ukraine is ready to fight a war with Russia -- the country's own estimates suggest only 6,000 of its 41,000 ground troops are combat-ready and more than 70 per cent of its armoured equipment is obsolete. Nonetheless, Turchynov's statements suggest Ukraine would be willing to fight back in the event of a Russian invasion of the mainland, so at the very least, this would not be the same kind of mostly bloodless affair Crimea was.
As military analyst Pavel Felgenhauer argued a few weeks ago, the Kremlin has a limited window of opportunity if it wants to do this -- it would probably want to invade before the May 25 election gains the new Ukrainian government more stability and legitimacy, and a planned rotation of Russian military conscripts also speeds up the timetable.
Given how long the world has been watching this situation, one would also imagine Ukraine's international backers have some sort of response planned -- seemingly not the case prior to Crimea, when Western governments seemed to be caught flat-footed.
It seems quite possible Russian President Vladimir Putin may not yet have decided on plans for eastern Ukraine. But whatever he decides -- we'll probably know soon.
Joshua Keating is a staff writer at Slate focusing on international news, social science and related topics.