Russia has long objected to NATO’s eastward expansion, and the prospect of NATO membership for the Ukraine and Georgia could put the alliance along Russia’s western border. Tensions with NATO have risen since the brief 2008 Russo-Georgian War.
Ukraine’s push for NATO membership could be put on hold indefinitely depending on the results of the upcoming runoff vote, while NATO is said to have serious problems with Georgia’s democratic credentials. In either case the prospective membership seems at best a few years off.
But Russia has also expressed concern about US plans to put missile interceptors in Eastern Europe, a dispute which seemed like it was going to die with the cancellation of the Czech-Poland base plans. Now the US is putting interceptors in eastern Poland and Romania, causing Russia to once again look askance at a plan ostensibly aimed at Iran, but clearly placing US defensive systems squarely along the Russian frontier, and mostly outside of Iran’s hypothetical range.