The constitutional court chairman will look at Lisbon again
Czech senators opposed to the EU's Lisbon Treaty could delay adoption of it for months, a Czech constitutional court spokesman has told the BBC.
At least 17 Eurosceptic Czech senators have signed a petition against the treaty, which they plan to submit to the court at the end of September.
The spokesman, Vlastimil Gottinger, told the BBC that a full treaty review might take as much as nine months.
"But I would guess three or four months - it depends on the petition," he said.
A further threat to Lisbon would emerge if it is not ratified in time for the UK general election, expected next April or May, which the British Conservatives are favourites to win. They have pledged to put Lisbon to a UK referendum if it is not yet in force.
The Eurosceptic Czech President, Vaclav Klaus, has been quoted as saying he will not sign the treaty until the constitutional court has considered the senators' petition. His signature is necessary to complete Czech ratification.
The treaty - aimed at streamlining EU decision-making - cannot enter into force until all 27 EU member states have ratified it. Nearly all of them have done so.
The Republic of Ireland will hold a second referendum on Lisbon on 2 October.
Irish voters rejected the treaty last year, but EU governments, anxious to bring the treaty into force, then gave Ireland legally binding "guarantees" that Lisbon would not affect key aspects of Irish sovereignty. These Irish guarantees have not yet been attached to the treaty.
The treaty's opponents say it undermines national sovereignty and concentrates too much power in Brussels.
The Czech constitutional court has already ruled that the treaty does not conflict with the Czech constitution. But that ruling addressed broad treaty issues, such as sovereignty and supra-national powers, rather than specific articles of it, Mr Gottinger said.
"Once the petition is filed, the court must ask the Chamber of Deputies and the Senate for statements, and then must review the petition. It will take many weeks to do that," he said.
"The court will probably be asked to review the whole [treaty] document," he added.