With the citizens of Bombay still mopping up the blood on their streets and counting the corpses in their hotels, attention has quickly turned to who is behind last week’s terror attacks. India says it has evidence that the gunmen who tore through its richest city were trained in Pakistan, and raised its security status to "war level" as a result.

This is no idle move: India and Pakistan have gone to war three times since the 1947 partition. But in the decades following their last conflict in 1971, over the birth of Bangladesh, both nations have acquired nuclear weapons. The prospect of war in the region now is chillingly freighted with images of mushroom clouds and death on a scale that would dwarf even the horror we have witnessed, live on television, over the past few days.

Pakistan’s president, Asif Ali Zardari, knows all about the threat of Pakistan-based militancy, extremism and terror. His own wife, Benazir Bhutto, was assassinated last year by an Islamist suicide attacker. He has pledged to crack down on extremists in Pakistan - if India does supply proof that is where the Bombay attackers originated. Given that just two months ago he described jihadi groups fighting in Kashmir as "terrorists", even though they are traditionally labelled "freedom fighters" in Pakistan, he may mean what he says.

But balancing conflicting demands - from an army that views India as an existential threat, from tribal groups forging closer ties with the Taliban and from a population that often feels it is an exploited pawn in America’s war on terror - has never been easy for leaders in Pakistan. Pervez Musharraf was able to use his controversial dual role as army chief of staff and president better to control both civilian and military grumblings.

But Mr Zardari has no comparable influence. In the same interview denouncing "terrorists" in Kashmir, he also said that "India has never been a threat to Pakistan". Such comments stir deep discontent within Pakistan’s military. It is split between two potential fronts: Kashmir on its north-eastern border and its tribal regions to the north-west, but there is little doubt it sees the conflict with India to the east, not with extremism to the west, as its most important battle.

Clearly, Mr Zardari does not agree, and his apparent determination to pursue détente must be applauded. Both he and the army may claim to have Pakistan’s long-term security at heart, but, in a nuclear region, who wins the dispute over how best to attain that has ramifications for us all. The battle is over in India, but it may be just beginning in Pakistan.