As negotiators resume the START talks, Poland’s defense minister announced this week that a Patriot missile battery scheduled for deployment in Poland in 2011 will be placed in the northeastern town of Morag. This will put the Patriots near Russia’s Kaliningrad enclave, a strip of land on the Baltic Sea sandwiched between Lithuania and Poland. It also will put U.S. Army troops there to operate the missiles.

Poland says the decision to site the battery in Morag is based on its quality of infrastructure and not on concern about Russia. Russian Foreign Minister Sergei Lavrov says he doesn’t understand the need to “create the impression as if Poland is bracing itself against Russia.” Both are being coy: putting the Patriots in Morag is Warsaw’s response to the huge military exercise in September in which the Russians postulated a Polish attack on Kaliningrad and simulated nuclear-missile launches against Poland.

We need not expect Russia to overreact to this development, for the simple reason that the Patriot battery’s defensive radius is limited. It can’t interfere with Russian ICBMs launched at North America. The area of Europe it can defend is small. These factors make it a proposition different from Bush’s silo-based interceptors. But a Russian military official has already stated that the Patriot deployment will prompt Russia to enlarge its Baltic Sea fleet. That statement was “clarified” only hours later with the explanation that fleet improvements in the Baltic would not be contingent on the status of the Patriots.

These disclosures, which have been trotted out with remarkable efficiency, are directed at the European audience that will be made uneasy by growing Russian power in the Baltic. The Patriot deployment presents an opportunity for Russia to justify ratcheting up its own military presence in the area. Having the battery removed won’t be an urgent objective for Moscow; indeed, the Patriots will serve a purpose for Russian policy as long as they are there.

Russia can’t enlarge its military footprint overnight, but it can have at least some of its forces on a new footing before the end of Obama’s first term. The American soldiers manning the Patriot battery in Morag, meanwhile, will be a very small contingent in a forward location performing a somewhat politically ambiguous function. U.S. officials need to be vigilant and proactive in defining the policy we are pursuing with this Patriot deployment. Eastern Europe, perennially the target of Russian aggression, is already thinking along the lines of General Ferdinand Foch in the months before World War I. When asked by a British counterpart what would be the smallest British military force of practical assistance to France, Foch replied: “A single British soldier — and we will see to it that he is killed.”