Venezuela's entry, assuming it goes ahead, puts a question-mark over Mercosur's newly established dispute-resolution tribunal, as well as its plans for closer macro-economic co-ordination.

ECONOMIST: A trade group becomes an energy club

Hun Sen equivocates over the tribunal not only for "national reconciliation" reasons but because of economic necessity and geopolitics.

CNN: BIG BURDEN

Mr Djindjic and Mr Kostunica and their respective parties joined forces in 2000 to oust former president Slobodan Milosevic, but have clashed over a range of issues, including economic and legal reforms, and co-operation with the international war crimes tribunal in The Hague.

BBC: Serbian coalition nears collapse