The Yugoslav parliament has voted in favour of a plan to abolish the Balkan federation and replace it with a looser union between its last two remaining members, Serbia and Montenegro.
The move clears the way to flesh out a new constitution from the blueprint, pushed through by the European Union in March. The West is keen to head off a Montenegrin drive for independence that it fears would destabilise the region.
The Serbian and Montenegrin parliaments had already approved the plan, which would consign Yugoslavia to history after more than seven decades of existence in various forms. But analysts and diplomats still expect protracted battles over the details. The upper house passed the plan by 23 votes to six against and the lower house approved it by 74 to 23 against.
The new state, called simply Serbia and Montenegro, would give the two republics broad autonomy within one internationally recognised state with its own president, parliament, cabinet and army to replace the current federal institutions.
The original plan, signed by leaders from all sides and EU foreign policy chief Javier Solana, envisaged that a new constitution would be ready for consideration by the three parliaments by the end of June.
However many analysts, diplomats and politicians say interpretations of the blueprint and ambitions for the new union already differ so widely that the prospect of agreement by then - or any time soon - is remote.
Lower house Speaker Dragoljub Micunovic said he expected the new draft constitution to be finished by the autumn. Yugoslavia would cease to exist when it is adopted.
Under the most optimistic plan, this could be completed this year, Micunovic told reporters.