The decision of the Albanian government to hand over control of its airspace, ports and military installations to NATO is the culmination of an intricate process of diplomatic consultations and planning which went on inside the alliance for more than a week.
The ostensible reason for this decision is a mortar attack from Yugoslav territory on a neighbouring Albanian village; as the poorest and least defensible country in the region, Albania had to resort to NATO protection.
But the spectacular nature of this move and the very public nature of the announcement (during a live television link-up in the middle of a UK Ministry of Defence press conference in London) indicates that it touches wider strategic calculations. Put simply, NATO has opted for Albania as the bridge-head for a possible ground offensive.
The build-up of NATO forces in the region continues unabated. The US decision to dispatch 2,000 of its soldiers last week was quickly followed by a NATO promise of a further 6,000 and the announcement over the weekend of a boost in the number of A-10 "tankbuster" aircraft.
Technically, the purpose of the force is purely humanitarian, to provide protection for the Kosovo refugees. In practice, the arrival of Apache helicopters and multiple rocket launchers is designed to blur the distinction between a purely air operation and a land offensive.
The decision to launch such an offensive has not been formally taken and NATO foreign ministers, meeting yesterday in Brussels, have officially not discussed this issue. But the momentum behind such an operation is virtually unstoppable; the only question is whether the entry of NATO troops into Kosovo will be unopposed, or whether the alliance would have to fight its way in the province.
NATO's original plans for a ground offensive called for the deployment of up to 120,000 troops, complete with the heaviest possible equipment. Depending on the impact of the current air campaign and the losses suffered by the Yugoslav military, the alliance may be able to scale down its plans. But even then, the military is used to planning for the worst possible alternative, and has to have credible resources to escalate NATO's involvement should the Yugoslav military provide stiff resistance.
This, in turn, calls for hefty supplies of troops and equipment, kept in reserve near the theatre of operation. And that requires the support of neighbouring countries.
The original plans envisaged a steady build-up of what the military generically calls "assets" in Macedonia. But the NATO-Macedonian link looks distinctly shaky. Macedonia has always opposed an independent Kosovo, since it contains a sizeable ethnic Albanian minority which may be infected by the troubles across the frontier. As long as NATO's aim was simply to police an autonomy deal for the Kosovo Albanians, Macedonia was happy to act as the base for Western troops.
But in the last week the alliance has obtained various indications that the Macedonians are also talking to the Yugoslav government. The shabby way in which Kosovo refugees were removed by the Macedonian authorities just as Yugoslavia closed its borders is the first indication of this covert understanding between these two Slav nations.
The current NATO force will remain in Macedonia. Nevertheless, the country cannot be relied upon to act as the base for a more sustained alliance ground effort. Another possibility is to use the Greek ports further south in the Balkans. But this is also fraught with difficulties for, although the Greek government has not vetoed NATO's action against Yugoslavia, an overwhelming majority of ordinary Greeks are against the operation.
The only remaining alternative is Albania itself. This is the conclusion which alliance planners reached over the weekend.
At first glance, this choice makes perfect sense. Albania is determined to protect its kith and kin in Kosovo and is guaranteed to allow just as many troops as NATO could ever muster. The country is also close to Italy where most of the NATO operation is headquartered. But in almost every other respect the choice of Albania was made out of necessity rather than conviction.
The country is dirt poor and has an appalling transport infrastructure. Its ports are in an advanced state of decay. NATO has insisted on taking control over these facilities directly, precisely in order to overcome such drawbacks.
And the political difficulties are just as important. The Albanian government has explicitly stated that its aim is to see an independent Kosovo. In all probability, the country does not want unification with Kosovo, although this remains a long-term historic goal.
Ethnic Albanians are divided into two distinct communities, and much of the violence which engulfed the country two years ago was due to this division.
Sali Berisha, the country's first post-communist leader, came from the north, where there is great support for the Kosovans. But the country's current Prime Minister, Mr Pandeli Majko, comes from the south, an area in which a Greek ethnic community also resides. Mr Majko is keen to portray himself as an ally of NATO. But he may be less enthused by the possibility that NATO will forge closer relations with the Kosovo Albanians, thereby raising support for ex-president Berisha, who already tried to topple the Albanian government in the recent past.
NATO is calculating that its presence on the ground would keep control over both Albanians and their brethren in Kosovo.
The author is Director of Studies at the Royal United Services Institute in London