The first mistake of the Ukrainian revolutionaries was to abandon the agreement of Feb. 23 to create a national unity government, including some of the revolutionary leaders, that would administer the country until new elections in December. It would have left President Viktor Yanukovych in office until then, but with severely diminished powers, as the constitution would have been changed to restore the authority of parliament.

Leaving a man who ordered the murder of dozens of protesters in power even temporarily was a bitter pill to swallow, but it had tacit Russian support because it saved President Vladimir Putin�s face. However, the crowds on Independence Square refused to accept the deal, and Yanukovych was forced to flee.

Parliament subsequently ratified his removal, but it was the mob, and especially the right-wing fighting groups like Praviy Sektor, who led, and the leadership who followed. Putin was humiliated, and he was given the pretext for claiming that Ukraine had fallen to a "fascist coup" as a justification, however flimsy, for rejecting the legitimacy of the new Ukrainian government.

The second grave error � and this one was entirely unforced � was the new government�s decision to repeal the law giving Russian equal status as an official language in provinces with large Russian-speaking populations. It delighted Ukrainian-speaking ultra-nationalists in the west of the country, but it needlessly alienated the two-fifths of Ukraine�s population who speak Russian as their first language.

So now Putin is bringing pressure on the new Ukrainian government by backing a secessionist movement in Crimea (where three-fifths of the people speak Russian). The rubber-stamp Russian parliament has also granted him authority to use Russian troops elsewhere in Ukraine to "protect" Russians � by which it seems to mean Ukrainians in eastern Ukraine who speak Russian, although they are not actually under attack.

Putin has not yet sent Russian troops into the eastern parts of Ukraine. However, pro-Russian crowds have appeared in cities like Kharkov, Donetsk and Lugansk demanding Russian "protection" � amid plausible reports that many people in those crowds are actually Russians imported from just across the border for the occasion, and not Russian-speaking Ukrainians at all. The promised Ukrainian election on May 25 may never happen.

The Ukrainian army has been mobilized, and actual fighting could be only days away if the Russians invade eastern Ukraine, or attack the encircled Ukrainian garrisons in Crimea. Maybe Putin is just bluffing; more likely, he doesn�t yet know himself how far he is willing to go. But one thing generally leads to another, and some bluffs are hard to walk away from. Are we on the brink of a new Cold War?

It wouldn�t be a hot war, except in Ukraine. Nobody will send troops to defend Ukraine, nor should they. Nobody is in position to stop Russia from conquering Ukraine if it chooses to, and turning it into a wider European war (or a world war) would not help matters.

In any case, Moscow would probably not try to conquer ALL of Ukraine. Kiev and the the west would fight very hard, and after they were defeated they would continue to resist a Russian occupation with guerilla tactics, including terrorism. Putin doesn�t need that, so part of Ukraine would remain free, and call for outside help.

It would come, in the form of financial and military aid, and maybe even what has hitherto been rigorously excluded from the discussion: NATO membership. And there Russia and everybody in NATO would sit for the next 5 or 10 or 20 years in a frozen confrontation that would include a trade embargo, an arms race, and a remote but real possibility of a nuclear war.

This is not at all what Putin intends or expects, of course. He is calculating that once he controls the Russian-speaking parts of Ukraine, he will be able to enforce a restructuring of the country as a federation in which the government of the eastern, Russian-speaking part will be permanently under Russia�s thumb, and will have a veto on the decisions of the central government.

That�s all Putin wants out of this: a Ukrainian government that always respects Russia�s wishes. It could even pursue a different policy on issues like human rights, if it wants (so long as it doesn�t give Russians ideas). He doesn�t want to micro-manage the place. He�s not out to conquer the world. He�s not even out to re-conquer Eastern Europe.

But Putin�s calculations about Ukraine have been wrong every single time since the turn of the century. He backed Yanukovych before 2004, and the Orange Revolution proved him wrong. He backed Yanukovych even more enthusiastically after 2010; the policy blew up in his face again. And here he is yet again, backing Yanukovych as the president-in-exile of his Russia-friendly fantasy version of Ukraine.

His calculations are wrong. If he continues down this road, he will cause a quite needless political disaster.

Gwynne Dyer is an independent journalist, based in London, whose articles are published in 45 countries.