The main part of the area was the Romanian province of Bessarabia,
annexed by Stalin and added to the Soviet Union after the Stalin-Ribbentrop
Pact of 1939. When it was recovered from German occupation at
the end of the second world war Stalin added a Russian speaking
territory - Transdniestria.
The conflict is between the Romanian speakers and the Russians
(as well as the Christian Turkic speakers, the Gagauzz). It seemed
at one time likely to end in the reunion with Romania. However,
this ought to happen only after the Russians and Gagauzz have
the chance to opt out by referendum. But even if the Russians
can opt out the problem then arises that they might become part
of Ukraine, which is rather hostile to Russian speakers. It is
because of these difficult to resolve problems that Moldova remains
independent. The disputes here have something in common with
those in Georgia and the Caucasus.