By Stephen Mulvey
Ukraine has not experienced the kind of intense political dramas seen in Russia and some of the other former Soviet states in the last 15 years, but now its turn may have come.
Protesters have been flooding onto the streets
An election widely regarded as falsified, thousands of people on the streets, the official result rejected by a number of cities, parliament going into emergency session - it is a unique situation and no-one can tell how it will end.
The closest parallel is the series of massive anti-government demonstrations in 2000 and 2001, following the murder of the opposition journalist Georgiy Gongadze.
Then, the largest political demonstrations the country had ever seen shook the government, but it did not fall. Eventually the protests died away.
Young and angry
One of the organisers of those protests, Yuri Lutsenko, is involved again this time around.
There is also a new group, Pora, mainly made up of students, which is prepared to take considerable risks.
Can Mr Yushchenko seize the moment?
On Sunday, some of them lay underneath buses to stop pro-Yanukovych voters with absentee ballots being transported to polling stations far from their homes.
Like the Georgian group Kmara, which played a key role in that country's Rose Revolution, they have reportedly received training from Serbian youth activists in the Otpor movement who helped oust Slobodan Milosevic when he refused to accept his election defeat.
On Monday, at least one Georgian flag could be seen being waved in the demonstration that filled Kiev's Independence Square.
But no-one yet knows whether Pora is made of the same mettle as Kmara or Otpor, or how far ordinary Ukrainians will support the campaign of civil disobedience that the opposition has called for.
Viktor Yushchenko, the opposition leader whom the demonstrators regard as the real victor of the election, does not on past record have the same driving ambition as his Georgian counterpart, Mikhail Saakashvili.
Parliamentary political alliances could sway the outcome
He is a banker, rather than a daring political animal with a burning sense of mission. It is not easy to envisage him storming buildings with his supporters, as Mr Saakashvili did.
Whether the political head of steam continues to build behind Mr Yushchenko will also depend on the parliament, where his supporters and those of Mr Yanukovych are roughly evenly balanced.
All eyes are currently on the speaker of parliament, Volodymyr Lytvyn, whose Agrarian Party is theoretically allied with the so-called Majority supporting Mr Yanukovych, but could, it is thought, end up on Mr Yushchenko's side.
The other key players in the post-election drama are the courts.
Many complaints about alleged election irregularities have already been registered.
"There is a possibility that the results from about 40 polling stations, mainly in the east and south of the country, will end up being cancelled," says Svetlana Dorozh, head of the BBC Ukrainian Service's Kiev bureau.
"People are talking about two million votes that have allegedly been falsified. It's enough, theoretically, to turn the election into a victory for Victor Yushchenko."
There is no doubt that the courts will be conscious of the huge public demonstrations of support for Mr Yushchenko as they consider these complaints.
They will also be aware, however, of the risks involved in crossing the men who have run Ukraine for the last few years - with the support of the country's most powerful and ruthless business tycoons.