There has been much speculation of late about a possible Russian intervention in Ukraine. After Russia ordered large-scale military exercises on Ukraine’s border earlier this week, for example, U.S. Secretary of State John Kerry warned that “any kind of military intervention that would violate the sovereign territorial integrity of Ukraine would be a huge, a grave mistake." And NATO Secretary General Anders Fogh Rasmussen tweeted today, “I urge Russia not to take any action that can escalate tension or create misunderstanding.” It seems that Western policymakers are most worried about two possible scenarios: First, that Russia would embargo gas to Ukraine, and second, that it would invade Ukraine’s Crimean peninsula. Is either of these two really likely?

Russia has used natural gas as a weapon against Ukraine twice before. In January 2006 and 2009, its state-controlled Gazprom corporation shut off pipeline deliveries to Ukraine in response to pricing disputes. Most Russian gas sales to Europe transit through Ukraine, so Russia’s move left some EU member states facing significant heating-fuel shortfalls in the dead of winter. These countries could have looked for a new provider, but they did not. They bought into Russia’s narrative that Kiev, not Moscow, was responsible for the pipeline shutoff. Today, EU members still purchase about a third of their natural gas from Russia, with contracts that run through 2020. Some nations have even increased their buys from Russia, since Gazprom offers the cheapest gas around.

That might be interpreted as evidence that Russia could again embargo gas to Ukraine with impunity. But things are different now. The European Union’s new eastern member states -- those that are the most dependent on Russian gas and hence suffered the most in earlier crises -- have prioritized new infrastructure projects to facilitate imports of liquid natural gas (LNG) from western Europe and elsewhere. They are also exploring natural-gas alternatives for electricity generation. These projects are not yet cost competitive and will take years to come fully online. But when they do, and as the shale revolution expands global LNG supply, Gazprom will face an increasingly uncertain future in Europe and with its major alternative pipeline customer, China. In other words, this is no time for Gazprom to embargo gas to Ukraine and risk angering Europe. Further, given Russia’s recent economic stagnation, it can ill afford to lose any revenue, and gas exports make up one of the largest contributors to overall Russian tax intake.

What about a military invasion that mirrored Moscow’s capture of South Ossetia and Abkhazia in the August 2008 war in Georgia? Of particular concern is the Crimean peninsula, which first became part of the Russian empire under Catherine the Great (it had changed hands among empires several times before then). In the 1940s, Soviet leader Joseph Stalin forcibly deported Crimea’s native Tatar population, and ethnic Russians have been in the majority ever since. In 1954, when both “Ukraine” and “Russia” were meaningless designations for constituent Soviet republics with no hope of independence, Soviet Premier Nikita Khrushchev artificially transferred the Crimea to Ukrainian jurisdiction as a rather bizarre gift. And the 1990s saw pitched legal battles about Crimea’s status after the Soviet collapse. It was ultimately named an autonomous republic of Ukraine -- although with very limited autonomy from Kiev.

The Crimean port of Sevastopol still hosts Russia’s Black Sea Fleet, which participated in the 2008 Georgia war. In a 2010 treaty that ended the second natural-gas crisis, Ukraine gave Russia a lease on the Sevastopol base through 2042 in return for a gas price ceiling. (That is another reason why Russia will not use the gas weapon now -- to do so would upend that treaty.) Although the fleet itself, like much of the Russian navy, is not in prime condition, the base could be used to bring Russian personnel ashore.

Still, it is unlikely that Russia would show the same zeal for fighting Ukrainian military forces as it did for fighting Georgian ones. The Ukrainian military is more than four times the size of Georgia’s, and it has a long history (dating from Soviet times) of preparing to be on the frontline of a major war. Even against the relatively insignificant Georgian forces in 2008, moreover, Russian forces displayed some significant operational weaknesses.

There is another reason for Russia to avoid invasion: Leading members of the Ukrainian officer corps, including Acting Defense Minister Volodymyr Zamana, have demonstrated a pro-Western mindset, and it would be extraordinarily risky for Russian forces to try to face them down. Hundreds of Ukrainian troops have cooperated closely with the United States and NATO in difficult and dangerous foreign operations in Bosnia-Herzegovina, Kosovo, Afghanistan, and Iraq, making them comrades in arms with their Western counterparts. The United States has trained more than 500 Ukrainian officers on American soil through the International Military Education and Training program, providing further opportunity for the growth of pro-Western ideas.

Yet there is one scenario that might convince Russia to take action: significant violence against Crimea’s Russian population. Threats against ethnic Russians would resonate at home. In response, Russia might offer to provide armed “peacekeeping” assistance to its beleaguered co-ethnics, much as it did in Moldova’s Transnistria in the 1990s. In recent days, Russian nationalists, Ukrainian nationalists, and the returned Tatar minority have all rallied in Crimea. So far, the protests have remained relatively peaceful, although fistfights did break out between opposing lines of demonstrators at the Crimean parliament building in Simferopol, which pro-Russian masked men have since occupied. If anti-Russian protests turned truly violent -- for example, if weapons-wielding ultranationalist fringe groups similar to those active in Kiev last week, get involved -- then Russia might send in small contingents from the Sevastopol base to protect Russian locals.

Although Ukrainian forces could in theory fight them, the decision to do so would be difficult, given the pro-Russian majority population of Crimea, the likelihood of pitched violence between any Russian interveners and Crimea’s returned Tatars, and the overriding need to prevent fires in tinderboxes elsewhere in Ukraine. Furthermore, U.S. and European policy leaders have warned against Russian military intervention, but it is not clear what they would do to stop it. It is unimaginable that war-weary and austerity-burdened NATO would send forces into a Ukrainian civil war to fight Russia. The West could level sanctions against Russia, but it is not clear what those would entail or how they would work. After all, Europe and Russia are codependent on their shared gas pipelines.

It might be tempting to believe that Crimea could be partitioned off to Russia, thereby ending the crisis. But approximately 40 percent of Crimea is not ethnically Russian, and a significant minority is viscerally anti-Russian. Further, if the process of forced partition started, it is not clear where it would end, given Ukraine’s division into pro-Western and pro-Russian factions that do not neatly match up with provincial borders.

What does this mean for the United States and its allies? Most important, the West should do all it can to support an ethos of nonviolence in Ukraine, with a special focus on Crimea. Diplomats and democracy advisers should put all their efforts into educating Ukrainian civil society groups about effective peaceful protest activity, much as they did in Georgia during the Rose Revolution. They should also encourage Ukrainian police forces to prevent ultranationalist Ukrainian outsiders from entering Crimea.

Ukraine has a terrible history of violence, including large-scale ethnic cleansing under both Soviet and Nazi rule. It would be a tragedy if history repeated itself now. Anti-Russian protest violence in Crimea could very well be the flashpoint.