Russian Chief of the General Staff Nikolai Makarov said Tuesday that cooperation between NATO and Finland, and Helsinki's potential membership in the bloc, constitute a military threat against Russia's security. NATO issued a statement Wednesday calling such claims "baseless."

While Finnish officials have gone out of their way to say that recent cooperation and drills with NATO should not be seen as moves toward joining the bloc, this has hardly placated Russia. This is due to Finland's unique geopolitical position in relation to Russia.

Finland and Russia share a border roughly 1,300 kilometers (800 miles) long. Like most European countries that border Russia, Finland's history of independence is relatively short. The country was a part of the Russian empire from the beginning of the 19th century until the empire's dissolution in 1917. Before that period, Finland had been part of Sweden since the 12th century.

The 20th century was kinder to Finland as an independent state. Finland enjoyed a short stint of independence in the interwar period, but fought against the Soviets in World War II. Thanks to a deal struck with Joseph Stalin after the war, Finland was not re-incorporated into Russia (by then the Soviet Union) like many of Russia's former imperial territories. Instead, Stalin agreed to keep the Soviets out of Finland's domestic politics and not encroach upon the country's independence. In exchange, Finland agreed to stay out of the NATO alliance.

This was not the worst option for Finland, a country of 4 million people that shared a border with a global power of nearly 200 million people. Finland remained neutral and the Soviet Union stayed out of Finland all the way through the Cold War. This gave rise to the term "Finlandization," which has now been applied to several countries that retain neutrality in the face of a larger and more powerful neighbor.

But there are nascent signs that this arrangement may be shifting. More than 60 years later, the primary institutions created out of the Cold War — the European Union and NATO — are changing. The financial crisis has created serious questions about the strength and viability of the EU. NATO, now encompassing 28 member states, can no longer rally as a united bloc around the Russian military threat. While Finland and certain other NATO members do still worry about a resurgent Russia, those farther away — like Germany and France — are far less concerned.

In this context, NATO has weakened as an effective military alliance, and Finnish officials have a point when they say Russia shouldn't be concerned about their country joining NATO. But at the same time, Finland has in recent years sought closer ties in the security sphere with its Nordic and Baltic neighbors, countries that share many of Finland's security interests. Finland has held a growing number of military exercises with countries like Sweden and Estonia, and officials have announced that Finland could begin participating — along with Denmark and Norway — in the monitoring of Iceland's airspace under the Nordic Defense Cooperation framework beginning in 2015.

It is therefore not so much NATO that worries Moscow, rather the security threat of the member states that make up this bloc, particularly those closest to Russia. And in terms of importance, Finland is high on Russia's list.