Kuchma and his allies were determined to change the constitution in order to reduce presidential powers and strengthen those of the prime minister. They had argued that the reforms were needed to bring Ukraine's political system, where the president enjoys enormous power, including that of choosing the prime minister, into line with other European democracies.
Kuchma, due to retire this year after two terms in office, pressed ahead with plans to introduce the changes despite criticism from western governments and organizations.
Although the government can usually muster a simple majority in the 450-strong parliament, constitutional changes require a two-thirds majority. Supporters of the changes were relying on an alliance of powerful businessmen, many of whom owe their wealth to Kuchma, and Communists who loathe Yushchenko's pro-democratic and market reform policies.
But yesterday the proposals fell six votes short of the 300 needed to turn them into law following heated exchanges between rival deputies and an impassioned speech by Yushchenko.
Yushchenko, who also leads the Our Ukraine bloc, told parliament the proposed reforms amounted to what he called a "coup."
"Friends, I want to say one thing: one ought to change the constitution and introduce reforms with honest hands. You ought to do this openly, ought to do this honestly and not be the dupes of this government. And lastly, taking part in an 'attempted coup' is a political crime and I say that you take full responsibility for that," Yushchenko said.
The opposition is hoping the result will boost Yushchenko's chances in the presidential election. Former Foreign Minister and Our Ukraine member Boris Tarasiuk says, "This means that the regime -- which wanted to chop up the constitution -- has lost, and that Ukraine has won, the opposition has won, the Ukrainian people have won. I think the next victory will be at the presidential elections."
One of the failed bill's main sponsors, Stepan Havrysh, an ally of Kuchma and coordinator of the pro-presidential majority in parliament, said: "This is a blow for the authorities, but we will work on it." He said some pro-presidential groups would try to reintroduce the bill on technical grounds that it had been improperly amended before being put to the vote. However, the constitution forbids the measure being reintroduced in parliament for a year.
The leader of the Social Democratic Party, Victor Medvechuk, is credited with drawing up the changes. A member of his party, Ihor Shurma, today blamed the failure on what he called self-serving members of parliament.
"We have the sort of government that the Ukrainian people deserve, we have the sort of government with the sort of legislature that the Ukrainian people deserve. We have the sort of situation with political reforms that the Ukrainian people deserve," Medvechuk said.
Mykola Onyshchuk is a member of another pro-government party, the Party of Working Ukraine, Industrialists, and Entrepreneurs. Five of its 42 members abstained in yesterday's vote. Onyshchuk admits he was surprised by the behavior of some of his colleagues, but says he hopes there will be further attempts to change the constitution.
"One shouldn't over-dramatize what has happened,” he says. “The majority is a collection of parties and each has its own political priorities and different ways of maintaining discipline."
Opposition Deputy Yarolsav Kendzior from the Our Ukraine bloc says government suggestions that the vote was conducted improperly are wrong and reflect their desperation at the defeat.
"In my opinion, everything that happened occurred properly,” he said. “It was a big political defeat for a big political adventure. This big, all-Ukrainian lie which was being trumpeted for many months by all the mass media and really it had just one objective -- to prolong the existence of those business and political clans in the current government for an indefinite period."
Many in the opposition believe yesterday's result could divide the already fragile majority. Onyshchuk disagrees.
"As to what will happen with the majority -- we'll see. I don't think something drastic will happen tomorrow; the political factions and parties were created on certain foundations. I think the most important thing for Ukraine today is to maintain stability and for this situation not to lead to the worsening or restriction of democratic institutes," Onyshchuk said.
Opposition deputy Kendzior, however, thinks yesterday's vote will create big cracks in the majority.
"The most important thing is that the defeat of this operation is the beginning of the disintegration of this majority. Believe me, I know them -- I speak with a lot of deputies from different parties in the majority. In recent times they were using their remaining strength, their last strength, to keep together. [The] financial and administrative resources that were thrown into trying to ensure 300 votes and a government win have collapsed," Kendzior said.
The opposition expects the Easter holiday period could see plenty of behind-the-scenes political activity and some defections to Yushchenko's party.