Even as Arsen Avakov, Ukraine's interior minister, vows to restore order in the country's east where thousands of protestors wave Russian flags and storm government buildings, a different kind of emergency is rising on Ukraine's south-western border. Transnistria, Moldova's breakaway region, has decided not to attend a meeting of the "5+2" group which has been seeking a diplomatic solution to the 24-year-old conflict along the Dniester. With reference to Crimea, Transnistrian authorities are pressing harder than ever to join the Russian Federation.

The hour of truth in Moldova is fast approaching. Its pro-European coalition government led by Iurie Leanca wants association with the EU, but, like all its predecessors, is committed to the "reunification of Moldova" by means of "re-integration" of Transnistria. The reality, however, is that Moldova can be made whole only if it decided to turn east rather than west. Indeed, Moscow has offered Chisinau a path to joining the Customs Union, and hopes that the Communist-led opposition to the Leanca government might win the next election and take up the Russian offer.

The European Union seeks to strengthen the Chisinau government's hand. Starting this month, Moldovans will no longer need visas to travel to the Schengen countries. A significant part of Moldova's population work abroad—as far away as Italy and Portugal—for the lack of opportunity at home. When they think of the EU, they think of its more affluent member states. Yet the reality is that Moldova's European future may be more like Romania's present. To some, it is not inspiring. The Gagauz, a Turkic ethnic group enjoying an autonomy is its tiny region in the country's south, are looking to Moscow. So are many ethnic Bulgarians, which populate a neighboring county.

Given this, EU-minded Chisinau would be much better off politically without pro-Russian Transnistria, which, it should be recalled, has never formed part of an independent Moldovan state. Transnistrians feel a strong attachment to Russia; they voted in the past to join the Russian Federation; and they have recently adopted Russian legislation. The problem is that that land-locked sliver of land along the Dniester River has only two neighbors, Moldova and Ukraine. In better times, Moscow could rely on Kiev keeping Transnistria's eastern border open, and allowing the port of Odessa to function as the unrecognized state's main outlet to the wider world. Now, this arrangement is becoming ever more tenuous.

When President Vladimir Putin spoke with President Barack Obama and Chancellor Angela Merkel a week ago, he brought up the issue of Transnistria's "blockade". Should it come to that, the situation in the region would rise to a dangerous pitch.