New Delhi's decision to launch air strikes against alleged militant insurgents in the disputed province of Kashmir has elevated a historic and protracted conflict between India and Pakistan to new and dangerous levels.
India has vowed to continue the offensive until the Kashmiri insurgents have been driven out of its territory, even if this escalates to an open confrontation with its neighbour.
As always, Pakistan's reaction has been no less martial. So much is traditional between these two long-standing rivals, but the stakes are now higher, since both are in possession of nuclear weapons, whose potency was tested only last year.
The two countries have gone to war three times over Kashmir since gaining independence in 1947. There has also been an insurgency in the area since 1989; India regularly accused Pakistan of sponsoring this violence, while the government in Islamabad, although upholding its claim to the territory, has denied any direct involvement.
The spark was supposedly provided - at least as far as India is concerned - by the incursion of 680 Afghan militants who had apparently crossed the official Line of Control (LOC), a line created at the end of the 1971 war between India and Pakistan, and a border which effectively divides the province.
India has also alleged that the entire operation was planned by the Pakistan army in order to take over the strategically important road linking Srinagar and Leh, a route which is vital to Indian troop movements.
However, this strategic confrontation is not the only explanation for India's extreme actions for, as always, there are additional internal calculations. The most obvious of these is that India is once again in the grip of election fever: the Hindu Nationalist Bharatiya Janta Party (BJP) coalition government lost a no-confidence motion last month after barely one year in office and the country is expected to go to the polls this September.
The BJP is not averse to playing the nationalist card. Indeed, one of the main reasons behind its decision to press ahead with India's nuclear tests last year was the desire to court public opinion and strengthen the government's popularity.
The party also has a tradition of talking tough on the Kashmir issue: after its arrival in power, the BJP promised to deal with Pakistan from a position of strength and even suggested that it might allow its troops to pursue Kashmiri militants into Pakistani territory.
The old nationalist tricks evidently need to be played out again, with a fresh bout of elections expected this autumn.
Curiously, developments in the Balkans may also be having an impact. Like China, India has opposed NATO's action in Yugoslavia. The explanation is similar: India is deeply disturbed by the notion that any group of countries can decide to intervene in the internal affairs of another state, and decide that one part of a country's territory deserves special treatment because it is populated by another ethnic group which resorts to violence. Put simply, the parallels between Kosovo and Kashmir are just too close for comfort and, as far as Indian politicians are concerned, had to be rebutted soon.
More generally, New Delhi is also concerned about NATO's future role. Ever since the conflict started, Indian diplomats have joined their Chinese counterparts in expressing regular concern about the alliance's decision to move away from its old job of safeguarding the security of its member-states towards "a new strategic concept".
By acting in this way, New Delhi may be attempting to send a warning to the United States that it will not tolerate any interference in its internal affairs.
Finally, it is entirely possible that India has chosen to act now because it thinks that the world's attention is firmly focused on Kosovo.
The question now is how Pakistan will respond. In recent years the country has tended to try to match the Indians blow for blow. Following India's decision to conduct five nuclear tests in May last year, for example, Pakistan responded with six of its own.
Last month, after India decided to test its long-range Agni 2 missile, Pakistan responded with launches of both its long-range Ghauri 2 missile and the shorter range Shaheen.
As things stand, the chances are that Pakistan will not risk intensifying the conflict. Major governments around the world already have expressed their concern at New Delhi's actions; Pakistan, desperate to acquire new financial credits from the International Monetary Fund for its sagging economy, is certain to try to milk this for all it is worth.
However, the Pakistani Prime Minister, Mr Nawaz Sharif, will undoubtedly face pressure from hard-liners, particularly in the military, to respond to India's provocations.
The most likely response would be to conduct a further test of the Ghauri 2 missile. The conflict will simmer on, with the fearful addition of a nuclear deterrence game to the heady south Asian brew.
Damon Bristow is head of the Asia programme at the Royal United Services Institute for Defence Studies