When Vladimir Putin was president of Russia two years ago and asked what he would do if Ukraine joined NATO, he replied: "Russia would have no choice but to target its missile systems at Ukraine."
Russia's disputes with Ukraine reached a head last winter with its decision to stop supplying the country with natural gas. This caused gas shortages in neighboring countries as well.
Ukraine has been a source of tension in Europe for some years. Former Prime Minister Viktor Yanukovych was voted in as president in the Feb. 7 runoff.
In terms of area, Ukraine is the second-largest country in Europe after Russia. Its population stands at about 46 million.
Moscow wants to keep Ukraine under its influence as a "buffer zone." That's because it is strategically located between Russia and NATO member nations.
The United States and Europe have actively sought to engage Ukraine in the belief that if it embraces democracy and free market economic principles, the vast country will help maintain stability in the former Soviet bloc.
The Western policy of engagement played a part in the Orange Revolution, a series of protests that erupted in November 2004 against the allegedly flawed presidential election earlier in the year.
Viktor Yushchenko, the outgoing president, prevailed with the backing of the United States and Europe. His rival, Yanukovych, who was supported by Moscow, bowed out.
But the bitter power struggle that ensued within his administration prevented Yushchenko from dealing adequately with economic reform and political corruption among other key policy issues.
His pro-Western policy, as epitomized by his belief in early participation in the NATO alliance, invited retaliation from Moscow. This took the form of price hikes for natural gas.
Ukraine's economy deteriorated. It was further hurt by the global financial meltdown.
The Orange Revolution also exacerbated Russia's relations with the United States and Europe and set in motion the train of events that led to the Russia-Georgia crisis over missile defense.
Yanukovych is in favor of mending fences with Russia.
His election victory signifies that Ukraine, which has teetered between the East and the West since its independence from the former Soviet Union, is about to start making long-overdue adjustments in its domestic and foreign policies.
But in language, religion and culture, Ukraine is divided. The eastern region is under Moscow's influence and the western region is close to Europe and the United States.
This means that any partisan policy toward either region will readily destabilize not only Ukraine but also its neighbors.
The fact that U.S. President Barack Obama and other world leaders have congratulated Yanukovych for his victory suggests their hopes for stability in Ukraine.
Yanukovych's support base is in eastern Ukraine. He must try to stabilize the country with well-balanced policies so as not to drive a wedge between the eastern and western regions.
When Russia's relations with Ukraine become tense, Moscow invariably plays hardball with the West.
There have been times when this has affected Japan's dispute with Russia over sovereignty of the Northern Territories off Hokkaido.
Japan is Russia's neighbor on the east. The stability of Russia's western neighbor, Ukraine, is important for Japan, too.
--The Asahi Shimbun, Feb. 21