The idea of granting limited self-rule to rebellious parts of Ukraine's industrial war zone for three years has struck a note of disquiet among many lawmakers and much of the Kiev media.
But it was inscribed in a truce deal that Ukrainian President Petro Poroshenko and Russia's Vladimir Putin signed off on in February in the Belarussian capital Minsk.
Parliament voted by an overwhelming majority on July 16 to ask Ukraine's constitutional court to rule whether such changes to the basic law were legal.
The idea of militia-run regions holding their own elections and setting up separate police forces "do not break or limit the rights and freedoms of (Ukrainian) people and citizens," Brintsev said in the decision.
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The self-rule clause is part of a broader "decentralisation" proposal that should see Kiev cede some of its powers to all regions - and assign especially broad ones to pro-Russian lands - in the months to come.
One top Ukrainian deputy said a second of three votes on the changes should take place by the end of next month. Parliament would then need to muster a two-thirds majority in a final reading for the amendments to take effect.
Both Washington and its EU allies believe that autonomy could satisfy separatist fighters and remove any arguments Russia may have for arming and funding their campaign - support Moscow firmly denies ever giving.
But the suggested changes have been denounced as insufficient by the rebels and are unlikely to make an immediate impact on the ground.
Four civilians and three Ukrainian soldiers have been reported killed since yesterday in shelling attacks on disputed towns that straddle a frontline splitting the self-declared "people's republics" of Lugansk and Donetsk from the rest of Ukraine.
Poroshenko's critics question whether Ukraine will ever be able to rebuild its imploding economy with the east's powerful coal mines and steel mills still under the insurgents' control.