Today is a day to weep for the world's revolutionaries. Their bruised bodies, their lost lives- and their shattered dreams.
Not just those who have been out in the freezing streets and squares of Kiev and other Ukrainian towns and cities, but also those who were out not so long ago in Cairo or Tripoli, where as in Kiev, their passion and their courage brought them nothing but grief. People power meets brute power- and the cost is huge.
It's impossible to say yet how all this will end - but it may well be that when peace eventually returns to Ukraine, the protesters will, in effect, have lost. When a regime uses live ammunition against its own citizens, it has crossed a line. It cannot turn back, it cannot concede. It's hard to see what real prospect there can possibly be now of a meaningful negotiated settlement. Just as in Cairo and Tripoli (Syria is a tragedy of a different order), even the overthrow of a hated president may lead to a new reality that is no better than what went before. It gives me no pleasure to say this: revolutions are often in vain.
It is, alas, too easy to be swept up in the excitement of young protesters taking control of the streets, unfurling their banners, erecting their tents and singing their songs of defiance. TV cameras blinking down from the balconies of nearby hotels give us the impression of a people in revolt, an unstoppable wave of protest, sweeping away oppression and corruption.
But the cameras can lie. Yes, the people are there, and yes, for a time, they control the streets. But the real power is elsewhere, behind the heavy wooden doors in government buildings, in army headquarters- and sometimes in capital cities hundreds or thousands of miles away, where those with more power make their own calculations, in their own interests.
So let's look at what has been happening in Kiev. Nearly a decade ago, the protesters of the Orange Revolution were out in that same Independence Square, from where they successfully brought down a sclerotic, corrupt regime and prevented the fraudulent installation of a pro-Moscow president, Viktor Yanukovych. Today, that same Mr Yanukovych is in power- having been elected, more or less fairly, in 2010. With the all-important backing of President Putin, he is determined to stay there.
Here are the real battle lines: pro-Western protesters out on the streets, most of them young and dreaming of a Ukrainian future as part of Europe, up against a ruthless Kremlin autocrat who has a very different dream- of a Ukraine firmly in Russia's sphere of influence, beholden to Moscow politically, militarily and economically.
Ask Hungarians who remember 1956 what happens when popular protest confronts Moscow might. Ask Czechs who remember 1968. It doesn't require Red Army tanks to start rolling through the streets of Kiev for the answer to be the same: the people lose.
Yet it has not been forever thus. In 1989, in Romania, Bulgaria and across eastern Europe, brutal Communist dictatorships were indeed swept away by people's uprisings. Different time, different Kremlin. For Mr Putin, 1989 was the greatest disaster to befall Moscow in its recent history. He is determined not to let it happen again.
Only now, it seems, are Western policy-makers waking up to the new reality: as Obama's Washington has withdrawn from global engagement, weakened and exhausted by Afghanistan and Iraq, Putin's Moscow has leapt in to fill the gap. We have seen it in Syria, where President Assad survives only at Putin's pleasure, and now we are seeing it in Ukraine as well. Putin understands the nature of power, and he knows better than any other current world leader how to use it.
I do not believe that all revolutions are doomed to fail. In east Asia and Latin America, the ruthless military dictatorships that were the norm in the 1960s and 70s have long gone, swept aside by a combination of popular resistance and internal decay. Similarly in much of Africa, kleptocratic dictatorships have made way for democracies, at least in part due to the end of the Cold War and the removal of external Big Power support for military strongmen.
But nor are all revolutions bound to succeed. Especially not in countries like Ukraine, Libya, Egypt and Syria, with deep social and political divisions, where there is no national consensus and no tradition of political dialogue. It is easy to forget as we watch the terrible, apocalyptic images from Ukraine that President Yanukovych has plenty of supporters, just as President Mubarak did in Egypt and President Assad, despite everything, still has in Syria. (There is one important difference, though: neither Mubarak nor Assad ever won a properly contested election. Yanukovych did.)
I still want to believe in the power of protest. I am still an optimist who believes that the world is slowly becoming a better place, with millions more people able to live decent, fulfilling lives. But when I see what is happening in Ukraine, Syria, Egypt, Libya, Central African Republic - need I go on? - my faith, such as it is, is sorely tested.