Winner
Diverse in Unity
Czechoslovakia broke up not because Czechs and Slovaks couldn't put up with each other - actually polls show that majority of people in both parts of Czechoslovakia were against dividing the country.
The problem was that post-commie Czechoslovakia was stuck with a political system designed by Commies in the wake of the Russian invasion in 1968. Their version of "federalism" could only work in an one-party political environment.
After the revolution, it soon became clear how unworkable this system was. In fact, it took less than a FIFTH of MPs to effectively block ANY legislation. The federal government was paralyzed by fringe nationalist groups and populists who abused a bad economic situation in post-commie Slovakia for their own gain - but the funny thing was, even most of the Slovak nationalists didn't want complete independence as that would cut them off the Czech subsidies.
With federal government in paralysis, most of its power went to the two separate state governments - Czech and Slovak - which then became effectively independent on each other as the only bond between them were the federal structures.
In 1992, there were general elections in which center-right liberals won a landslide victory in the Czech part of Czechoslovakia. On the other hands, in Slovakia populist parties and nationalists won. Unfortunately, the only way to form a coalition on the federal level of government was a cooperation between Czech right-wing liberals and Slovak populist center-left nationalists.
When the coalition talks collapsed, suddenly everybody started talking about dissolution of the federation. The Czech government, in its infinite wisdom and against the will of most of the people decided that rather than to face another 4 years of government paralysis and bickering with the Slovaks over every penny, it would be easier to dissolve the federation. This was when the Slovaks backtracked and demanded not an actual independence, but a sort of Czech-Slovak confederation in which federal gov. would only take care of certain policies. Unfortunately for them, their "plan" was very ambiguous and the Czech gov. saw it as just another Slovak attempt to stop its liberal reforms and extract money from the Czechs, so it refused and told the Slovaks that if they don't agree on a plan to dissolve the federation, the Czech part will unilaterally secede.
From there, it went fast and in just few months, Czechoslovakia was dissolved. So, as you can see, it was more a result of chronic failure of the Communist-designed rigid political system, not a result of some sort of nationalist explosion (though it had played a part in this farce). With a better federal system of government, Czechoslovakia could have easily survived.
EU is entirely different, as it just forming up. If the federal government works, so will the EU.
