U.S. Secretary of State John Kerry and Polish Foreign Minister Radoslaw Sikorski  shake hands after signing a framework agreement on a Polish-American innovation program at a meeting in Warsaw on June 3. Kerry and President Obama were in Poland as part of a European trip. (Pawel Supernak/EPA)

On Wednesday, as President  Obama visited Poland, the U.S. announced that it would be spending $1 billion to boost its military presence in Eastern Europe. It's a big step, but for some in Poland, it may not go quite far enough.

“For the first time since the Second World War, one European country has taken a province by force from another European country,” Radoslaw Sikorski, the Polish foreign minister, told the New York Times before Obama's visit. “America, we hope, has ways of reassuring us that we haven't even thought about. There are major bases in Britain, in Spain, in Portugal, in Greece, in Italy. Why not here?”

It's a big proposition. Poland does have a small U.S. military presence, which was recently boosted with the arrival of 300 U.S. airmen and a dozen F-16 fighters for joint exercises this year. A major U.S. military base would be a major step up, however, and may be seen as contravening a 1997 NATO-Russia partnership that prohibited bases in Eastern Europe.

In many ways, Poland's position is understandable. There are obvious benefits to having a U.S. military base on your land. U.S. troops in Poland can help offset Polish security concerns, for example, and provide opportunities for more routine cooperation between U.S. and Polish troops. There are also economic factors: U.S. troops can spend money in the local communities, and the U.S. government may pay a lease on the land.

But there are bigger factors here for Sikorski. A U.S. military presence in Poland would be a forceful reminder that yes, the U.S. does still consider Poland a key ally, and yes, it is actually willing to stand up to Russia. That concept was called into question in 2009, when Obama scrapped plans for an anti-ballistic missile shield in Poland. At the time, Polish tabloid Fakt ran a front-page headline: “Betrayal! The U.S. sold us to Russia and stabbed us in the back.”

Recent events are putting the Poland-U.S. relationship under scrutiny again, none more so than Russia's apparent willingness to get involved in the affairs of its neighbors has left many in Eastern Europe concerned. Poland of course has history with Russia, much of it pretty nasty (the Katyn massacre, for example), and much like Ukraine, Poland's recent moves to integrate with Europe and NATO have created new strains too. A 2013 poll conducted by the BBC World Service found that just 19 percent of Poles thought Russia's influence was positive, with 49 percent thinking it negative.

Sikorski has been a key player in the Ukraine crisis, likely seeing parallels with Poland's own Solidarity movement that saw the country shake itself free of Soviet influence. Some critics say his viewpoint of Russia is outdated ("Like the thinking of many onetime Solidarity activists," Ola Cichowlas wrote at Foreign Policy recently, "his inability to see Russia as anything other than a continuation of the Soviet Union will blind him to the nuances of the situation") but he is widely seen as an important European leader, and a possible successor to Catherine Ashton, the European Union's current foreign-policy chief.

Of course, there are some issues with having a U.S. military base on your soil. In Poland's specific case, Russia may well view it as a provocation and a break with the 1997 NATO-Russia partnership deal that saw Western powers agree to not have “substantial and permanent” troops and bases in Eastern Europe. More broadly, there might be issues with sovereignty and nationalism: U.S. military bases in the Philippines and Japan have prompted a number of protests over the years. In practical terms, the bases themselves can sometimes end up costing the host countries a fair amount of money, too (for example, South Korea covers around 40 percent of the costs of U.S. military bases on its land).

It's also a discussion for the U.S. military, of course. There were more than 1,000 U.S. military bases around the world just a few years ago, and many question whether the bases in Europe (many of which are in Germany) are of any great strategic value. Sikorski has questioned this, too.

"At the moment, we have NATO bases as legacies of the Cold War, in places where they were useful during the confrontation with the Soviet Union, and it doesn't take into account the events of the last quarter of a century," Sikorski told CNN’s Christiane Amanpour on Monday. "And this should now be addressed.”