However, that's just not true.
The Baltic Countries were admitted to the United Nations on September 17, 1991. Estonia, Latvia, and Lithuania participated in the first meeting of the North Atlantic Cooperation Council as founding members on December 20, 1991, making them NATO partner countries five days before the Soviet Union ceased to exist on December 25, 1991.
NATO and Russia signed an agreement, the Founding Act on Mutual Relations, Cooperation and Security between NATO and the Russian Federation, in May 1997, but it does not include language restricting NATO from expanding into the Baltic Countries or placing military bases there. The only mention of the word "Baltic" is in this sentence: "Russia has carried out deep reductions in its armed forces, has withdrawn its forces on an unprecedented scale from the countries of Central and Eastern Europe and the Baltic countries and withdrawn all its nuclear weapons back to its own national territory."
There are other relevant sentences, with NATO and Russia agreeing to the principles of:
- refraining from the threat or use of force against each other as well as against any other state, its sovereignty, territorial integrity or political independence in any manner inconsistent with the United Nations Charter and with the Declaration of Principles Guiding Relations Between Participating States contained in the Helsinki Final Act;
- respect for sovereignty, independence and territorial integrity of all states and their inherent right to choose the means to ensure their own security, the inviolability of borders and peoples' right of self-determination as enshrined in the Helsinki Final Act and other OSCE documents.
Both parties agreed that neither one had a veto power: "Provisions of this Act do not provide NATO or Russia, in any way, with a right of veto over the actions of the other nor do they infringe upon or restrict the rights of NATO or Russia to independent decision-making and action. They cannot be used as a means to disadvantage the interests of other states."
Both parties agreed that nuclear weapons were not to be situated in the Baltic Countries, but that's not an issue today: "The member States of NATO reiterate that they have no intention, no plan and no reason to deploy nuclear weapons on the territory of new members, nor any need to change any aspect of NATO's nuclear posture or nuclear policy - and do not foresee any future need to do so."
The one sentence that Russians probably claim is the smoking gun is: "The member States of NATO and Russia reaffirm that States Parties to the CFE Treaty should maintain only such military capabilities, individually or in conjunction with others, as are commensurate with individual or collective legitimate security needs, taking into account their international obligations, including the CFE Treaty."
The Baltic Countries only possess a handful of modern fighter aircraft, putting the matter in perspective. Even now, the number of fighters in the combined Baltic Countries totals to 12. But from Russia's point of view, the part about "their international obligations" is a loophole large enough for Putin to drive a Lada through, with Russia whining that the territory near its borders should be free of foreign military equipment for a good number of multiples of the distance a BUK missile flies.
The border between Latvia and Russia was not settled until March 2007 because Russia refused to accept that its predecessor, the Soviet Union, had annexed the unwilling Latvia in 1940 via the Molotov-Ribbentrop Pact. The border between Estonia and Russia was not settled until February 2014 because Russia refused to agree on the language and conditions. Not coincidentally, there is a large number of Russians in these countries.
The problem has always been Putin and Russia.