Back in 2010 British-born Ukraine expert Taras Kuzio warned that the region could be "Europe's next flashpoint", and suggested a number of scenarios that Russia could use to engineer a takeover.
One of them - "sending security forces and Black Sea fleet personnel camouflaged as local paramilitaries to occupy Sevastopol in an overnight operation" - describes almost exactly what is thought to have happened last week.
As long ago as 2008, shortly after Russia and Georgia clashed in the South Ossetia war, the US academic Leon Aron warned that "Russia's next target could be Ukraine".
Mr Aron, director of Russian studies at the American Enterprise Institute, also thought the flashpoint would be the City of Sevastopol, home of Russia's Black Sea fleet and a large ethnic Russian majority.
"An early morning operation in which the Ukrainian mayor and officials are deposed and arrested and the Russian flag hoisted over the city should not be especially hard to accomplish," he wrote.
"Once established, Russian sovereignty over Sevastopol would be impossible to reverse without a large-scale war, which Ukraine will be most reluctant to initiate and its Western supporters would strongly discourage."Back in 2007-2008, during what journalist Ben Judah calls the "Short Cold War", Russia was bullying Ukraine with gas cut-offs to stop it moving closer to NATO. Georgia received far harsher treatment (partly because it was smaller, partly because Saakashvili gave Putin the opportunity). Now it's Ukraine's turn. Back then, Putin was also dividing Europe by courting Germany and Italy (unfortunately, Vladimir has since lost his soulmate Berlusconi).
Dr Kuzio says the new leaders of Ukraine have "played their hand really well" by refusing to be provoked into a "hot war". There are "more differences than similarities" with the South Ossetia crisis, where Georgia gave Russia an excuse to retaliate, he said.
He believes that the lack of widespread unrest in Crimea, and the relatively muted response from separatists to the arrival of Russian troops, may have taken Mr Putin by surprise.
Others echo the view that Mr Putin has had to react opportunistically to changing events. In a recent article, Dr Aron says Moscow has been "gradually escalating the pressure on Ukraine, seeing what works and what does not, pausing and looking over his shoulder at the response from the west".Which tallies with what I've been saying.