But all-out invasion of Ukraine appears unlikely at present given that even if Russia were to win, it would face years of costly and bloody insurrection.
Taking over just Crimea appears, at least initially, to be less risky given that more than half the population is ethnic Russian. As a peninsula, Crimea would be theoretically easy to defend.
But a Russian takeover of Crimea could be disastrous in the long run. The Kremlin would be underestimating the impact of the sizeable population of Tatars who were forcibly deported from Crimea by Josef Stalin in 1944 and not allowed to return until the beginning of political and economic reform in the 1980s.
Sutyagin, who is at the London-based Royal United Services Institute, said: "The Tatars are very anti-Russian. They will do anything not to be under the Russians. They will be determined to fight for Ukraine. It would be a second Chechnya."
Many of the soldiers fighting in the Ukrainian army are ethnic Russians but Sutyagin said loyalty to the idea of an independent Ukrainian state would top their ethnicity. "The entry of Russian troops would be a deep humiliation for Ukraine. Ukrainians do not want to be occupied. It is a mistake by Russian politicians who think ethnic Russians are Russian," Sutyagin said."
If the Tartars fight the Russians will just expel them to Ukraine.
Like they did in East Germany, Hungary, and Czechoslovakia?
Don't make me laugh.