Tuva, on Mongolia's north-western frontier, was the last territory annexed by the former Soviet Union. It fell into Stalin's grasp in 1944. Last week, Mr Yeltsin's chief of staff, Sergei Filatov, denounced Tuva as one of three republics - the others were Tatarstan and Bashkortostan in the Volga-Urals area - that were undermining Russia's unity with their separatist tendencies.
The trouble in Tuva began in September, when its council declared invalid Mr Yeltsin's dissolution of parliament in Moscow. Radical council members tried to force a vote on secession from Russia. That failed, but the council refused to obey Mr Yeltsin's orders to dissolve itself. Instead it adopted a constitution on 22 October that envisaged the creation of a new parliament and changed the republic's name to Tyva.
With Russia's electorate more than 100 million in number, the 200,000 or so voters in Tuva (as most Russians still think of it) are unlikely to have a decisive effect on the referendum or elections. But in larger republics such as Tatarstan and Bashkortostan, with nearly 4 million people each, a 'no' vote in the referendum could sink Mr Yeltsin's efforts to arm himself with sweeping powers in his draft constitution.
For the document to take effect, at least 50 per cent of Russian voters must cast ballots and at least half of those who vote must approve it. As the document drops all reference to the 'sovereignty' of republics, bans their secession and says their constitutions are subordinate to the Yeltsin draft, the incentive for a 'no' vote in the republics seems strong.
Thus, while the 'yes' vote is likely to be high in cities such as Moscow and St Petersburg, the result is less certain in republics such as Chuvashia, Mordovia and, above all, in the turbulent northern Caucasus. Mr Yeltsin spent two days in the Caucasus this week. He extracted a promise from the leaders of Ingushetia and North Ossetia to urge their voters to endorse the constitution.
Whether this will translate into support on Sunday is unclear. In the neighbouring Chechen Republic, it seems improbable that many voters will even take part in the referendum. Chechen declared independence from Moscow two years ago and shows no sign of backing down. In contrast, Mr Yeltsin seems assured of substantial support in the huge republic of Sakha (formerly Yakutia) in eastern Siberia. Its leaders co-operated with him during the power struggles of September and October, and he rewarded them later by allowing Sakha to keep all federal taxes raised on its territory.Reuse content