When Vladimir Putin announced the Kremlin's annexation of Crimea this week, he made it clear that the region's large Russian-speaking population made the move necessary and inevitable.
In fact, large populations of Russian speakers are common along the fringes of the old Soviet Union. Those groups are made up of a combination of indigenous people and Russians who migrated from the mother country, many as part of Soviet-era policies aimed at altering the ethnic makeup in potentially troublesome satellites.
And there's precedent elsewhere for Crimea-style interventions on behalf of ethnic Russians. As recently as 2008, Georgia's breakaway South Ossetia region was cleaved with the help of a quick thrust by the Russian army.
So, how nervous should the now-independent former Soviet republics be about what's happened in Crimea? Here's how things stand in four regions.
In the region roughly southeast of the Baltic states that includes Ukraine, Belarus and Moldova, all three have sizable ethnic Russian populations.
Belarus, with about 8 percent of its population Russian, enjoys warm relations with Moscow and has signed on (along with Kazakhstan) to join Russia's "Eurasian Union" trade bloc that The Guardian says Putin hopes will grow into a " 'powerful, supra-national union' of sovereign states like the European Union."
Meanwhile, Moldova's smaller Russian population (about 6 percent) is concentrated in Transnistria, an autonomous region that is trying to separate from the rest of the country. The analogy with Ukraine and Crimea couldn't be more stark, suggests The International Business Times.
Some 2,000 of the Kremlin's troops are enforcing a cease-fire in Transnistria between Russian separatists and the Moldovan government. Although the region borders Ukraine and not Russia, given the instability in Kiev and Transnistria's proximity to Crimea and the Black Sea coast, Moldova eyes it warily.
What's more, since the Crimean crisis broke out, Transnistria's local Parliament has asked Moscow to grant the breakaway region Russian citizenship and admission to the Russian Federation.
The Baltic States
Latvia and Estonia have significant ethnic Russian populations. About 27 percent of Latvia's 2 million people are Russian, as are about a quarter of Estonia's 1.3 million. According to The Telegraph, the Russians in Latvia migrated there during Soviet rule when they were able to occupy the top rungs of civil and political society.
"But ever since communism's collapse, the boot has been firmly on the other foot. Latvian, not Russian, is the official language, and the country is now one of NATO's newest — and keenest — members, along with fellow Baltic states Lithuania and Estonia," the newspaper writes.
According to Reuters, Latvia and Estonia in particular "are alarmed by [Putin's] justification for Russian actions in and around Ukraine as protection for Russian speakers there.
"While all three Baltic republics have joined NATO — and Lithuania next year should be the last of the three to adopt the euro — these small countries are largely dependent on energy from Russia and have strong trade ties," Reuters writes.
"Last weekend, as pro-Russian forces were surrounding Crimea, Moscow's ambassador to [Latvia] caused further unease by saying that the Kremlin was planning to offer passports and pensions to ethnic Russians in Latvia to 'save them from poverty,' " The Telegraph says.
Kazakhstan, with just under a third of its population ethnic Russia, is one of the Kremlin's key allies. The BBC says it's "Moscow's strategic partner and the two countries regularly hold joint military exercises. They have close trade links as both are trying to develop a common market." The relationship, it says, is comparable to the one enjoyed between the U.S. and the U.K.
"But Russia's military action in Crimea has created unease among Kazakhs. They are worried that a 'Ukrainian scenario' could also apply to this Central Asian nation," the BBC says.
Kazakhstan's northern Kostanay region is about half ethnic Russian, and in other regions, especially to the east, "there are fewer ethnic Kazakhs than ethnic Russians," according to The Washington Post.
On Monday, Kazakhstan's pro-Russian President Nursultan Nazarbayev was said to "understand" Russia's position vis-a-vis Crimea, according to Reuters, "which struck many as a very carefully worded way of phrasing it," according to the Post.
Kyrgyzstan, with about a 12 percent ethnic Russian population, also has a Kremlin-leaning president, Almazbek Atambayev. But the country has carefully balanced East and West until now, allowing both a Russian military base and a U.S. air base on its soil. That is set to change, however.
Transitions Online, a blog that monitors the region, says:
"Both Russian and U.S. air bases have been in Kyrgyzstan for more than 10 years, but the U.S. base will be closed by July. That decision was made by Kyrgyzstan's president immediately after his election in late 2011 and confirmed by parliament in June 2013. It is widely believed that it was made under pressure from Moscow.
"Most people in Kyrgyzstan supported the closure when it was announced, but Russia's incursion into Crimea to 'protect native Russians' has raised concerns in Kyrgyzstan and has changed some minds about the departure of the Americans."
While the Caucasus is home to only small minorities of ethnic Russians, it's a region that has suffered from the Kremlin's attentions. Chechnya has been the locus of a brutal separatist conflict with Moscow. Georgia saw its South Ossetia region cleaved by Russia's 2008 incursion.
In 1992-93, the breakaway Abkhazia region of Georgia also underwent a civil war in which ethnically Georgian militias, supported by the Georgian state, were pitted against "ethnically Abkhazian militias supported both by North Caucasus militants ... from Russia and by the Russian state itself, which provided weapons and training to the fighters and carried out airstrikes against ethnic Georgian targets."
It's clear too that the Crimea situation has raised concerns in Azerbaijan. The Moscow Times quotes Avaz Gasanov, director of the Azerbaijan Society of Social Science Research, as saying:
"It is still unclear what will happen to Crimean Tatars if Crimea joins Russia. ... We are not against the people of Crimea wanting to organize a referendum, but we are against the way it has been organized. The rush to hold the referendum and the presence of the Russian military is just not right," Gasanov says.