I'm wondering about the motivation regarding the apparently imminent addition of Montenegro to NATO.
I figured myself there might be four rationales, since Montenegro doesn't add significant military power of bases:
(1) The "European unification is good" ideology
(2) Prevention of Montenegro becoming a Russian naval and intelligence base
(3) Part of Serbia strategy, encircling Serbia and thus neutralizing its option to be close to Russia politically
(4) Payback to Putin for Ukraine et cetera
(4) was ruled out quickly because the process lasted for years already, and such a long process would be a poor fit for a payback for the South Ossetia conflict as well.
(3) seemed unnecessary since Serbia is tilting towards NATO heavily already
The motivations (1) and (2) still make some sense, and can indeed be found in an influential study on NATO enlargement of 1995, hosted proudly on the NATO.INT website:
Therefore, enlargement will contribute to enhanced stability and security for all countries in the Euro-Atlantic area by :
- Encouraging and supporting democratic reforms, including civilian and democratic control over the military;
- Fostering in new members of the Alliance the patterns and habits of cooperation, consultation and consensus building which characterize relations among current Allies;
- Promoting good-neighbourly relations, which would benefit all countries in the Euro-Atlantic area, both members and non-members of NATO;
- Emphasizing common defence and extending its benefits and increasing transparency in defence planning and military budgets, thereby reducing the likelihood of instability that might be engendered by an exclusively national approach to defence policies;
- Reinforcing the tendency toward integration and cooperation in Europe based on shared democratic values and thereby curbing the countervailing tendency towards disintegration along ethnic and territorial lines;
- Strengthening the Alliance's ability to contribute to European and international security, including through peacekeeping activities under the responsibility of the OSCE and peacekeeping operations under the authority of the UN Security Council as well as other new missions;
- Strengthening and broadening the Trans-Atlantic partnership.
This doesn't fit to my own stance that enlarging one's alliance or founding one should first and foremost have the net effect of improving the security of the own country. Instead, the Cold Warrior smell is powerful: NATO as the "Western" bloc facing pseudo-communist dictatorships running planning economies. Several of the reasons listed are furthermore very vague.
The list of requirements for joining from the same study doesn't fit 100% to Montenegro, nor to the existing NATO members (Portugal and Greece were dictatorships for much of their membership in NATO and Iceland still doesn't have a military).
Russia's voiced concerns about Montenegro's are laughable because adding such a small country to the behemoth NATO is negligible, but on the other hand Russia could (or does) correctly claim that the attitude behind such an enlargement is close to the Cold War's attitude of rivalling blocs.