Editor's note: Frida Ghitis is a world affairs columnist for The Miami Herald and World Politics Review. A former CNN producer and correspondent, she is the author of "The End of Revolution: A Changing World in the Age of Live Television." Follow her on Twitter @FridaGhitis.
(CNN) -- On Friday, armed men in military fatigues marched into the principal airport in Simferopol, the capital of Ukraine's most contentious region, Crimea. The uniforms did not reveal their identity, but an alarmed Interior Minister in Ukraine's new government declared the move an "armed invasion" by Russia.
The incursion came 24 hours after masked gunmen took over government buildings there, raising the Russian flag over the regional parliament in a defiant sign that the battle for Ukraine is far from over.
In Kiev, the pro-European activists who succeeded in bringing an end to the Russian-backed government of now-former President Viktor Yanukovych are making progress choosing a new government with a well-qualified prime minister. But in the Crimea, on the Black Sea, tensions are building.
The situation is serious and the risks are enormous. Crimea is the flashpoint. If Ukraine unravels, it will begin there, in the small peninsula that has played an outsize role throughout history. If Russia decides to launch a military intervention, its justification and its target will be the Crimea.
For that reason, Ukraine's new government must skillfully pay attention to how it deals with the concerns of the Crimean people and the status of that part of the country. At the same time, the U.S. and Europe must play a useful and constructive role, making sure Moscow understands that this must -- and can -- be resolved without military intervention, and that Ukraine will not be dismembered.
All of Ukraine shares a history with Russia. And the entire country is home to millions of Russian-speaking citizens. But in the Crimean region many of Ukraine's internal conflicts -- particularly its divisions regarding Russia -- are magnified.
The majority of residents are ethnic Russians. The rest are ethnic Ukrainians and Tatars. Many of the ethnic Russians feel a strong allegiance to Moscow. Some would like the region to break away and become independent of both Kiev and Moscow. Others would like it to become a part of Russia.
In a region where national borders have shifted with political and military convulsions for centuries, Crimea has changed rulers many times. During much of the Soviet period it was part of the Russian republic. Then in 1954, in a surprising and not wholly understood move, the Soviet leader Nikita Khrushchev gave Crimea to Ukraine. At the time, the redrawing of borders was not as meaningful as it is now. The Crimea was still inside the USSR, still ruled from Moscow.
Crimea was the stage for major historical events. In 1945, one of the most important of all Allied meetings was held there, when Franklin D. Roosevelt and Winston Churchill joined Joseph Stalin at a Black Sea resort for the Yalta Conference, where they planned the last phases of the war and started drawing the map of post-war Europe.
The peninsula was also the setting for the Crimean War in the 19th century, as the Great Powers fought each other for control of the Old World and of the pivotal Black Sea.
Crimea has strong historic, political, cultural and geographic links to Russia. But perhaps most important, it has paramount strategic value.
Take a look at a map to see it more clearly.
Look at the city of Sevastopol near the southern tip of the Crimean Peninsula. Sevastopol has long been a major naval port for Russia. Today it is the headquarters for Russia's Black Sea fleet.
Imagine you have Russian cargo -- say, weapons you want to send to your ally in Syria. The best route is through the Crimea, sailing toward Istanbul, then across the Dardanelles into the Mediterranean. In fact, the Russian navy needs Sevastopol in order to have access to the Mediterranean and to the Indian Ocean during the winter months. It has a smaller civilian port at Novorossiysk, a much inferior option.
Sevastopol became the subject of heated negotiations when the Soviet Union was collapsing. In 1990, Ukraine and Russia agreed to grant special status to the area, with a long-term lease for the naval facility running until 2047. The arrangement is vaguely reminiscent of the U.S. lease at Cuba's Guantanamo Bay.
With the collapse of the pro-Moscow regime in Ukraine last week, Russia sees a threat to its larger goal of maintaining a sphere of influence over its "near abroad," what used to be the Soviet Union. It wants to protect its natural gas pipelines across Ukraine. And it has a specific concern with preserving its facilities in Sevastopol. It also wants to protect Ukraine's ethnic Russians from discrimination.
The danger is that Russia will use the situation of Ukraine's Russian speakers as a pretext to achieve its other goals. It did that in 2008 when it invaded the Republic of Georgia and gave official recognition to breakaway regions as independent states.
Russian Foreign Minister Sergei Lavrov said Moscow would defend Ukraine's Russians "uncompromisingly." At the same time, President Vladimir Putin ordered military exercises on Ukraine's border and put 150,000 troops on alert. Russia's Interfax news agency said the Defense Ministry reported that "constant air patrols are being carried out by fighter jets in the border regions."
Some 26,000 Russian troops are believed to be stationed in Sevastopol. Ukraine's new President warned Moscow that if Russian troops leave their bases "it will be considered military aggression."
The unfolding drama -- seized government buildings, military forces on alert, uncompromising language -- gave cause for alarm to the countries' neighbors. Poland's Foreign Minister Radoslaw Sikorski called it "a very dangerous game," warning, "this is how regional conflicts begin."
It's hard to imagine that Putin has any interest in starting a war over Ukraine. But the new government in Kiev must take measures to prevent giving Moscow an excuse.
For the sake of Ukraine's future, it must include ethnic Russians in the government and ensure their equal status. In addition, Ukraine should reassure Russia that the Sevastopol lease remains unchanged by the change of government in Kiev.
These positions must have full backing from the West. Washington and the European Union must seek to lower the temperature, while making it clear that the dismemberment of Ukraine is unacceptable. As it happens, Russia and the U.S. agreed to precisely that in 1994, in exchange for Ukraine's relinquishment of its nuclear weapons.
The crisis in Ukraine, and the disputes that underpin it, are complicated. But they are not unsolvable. If ever there was a time for strong, decisive and wise diplomacy, it is now. The protesters in Crimea -- and anyone who backs them in Moscow -- should get the message that Crimea will remain part of Ukraine.