NEW DELHI - As Indian and Pakistani soldiers trade heavy artillery fire along the Line of Control dividing disputed Kashmir, an open military confrontation between the two nuclear rivals appears likely unless the United States is able to compel Pakistan to crack down on terror groups tied to its intelligence service.
The United States' critical role is reinforced by its military presence in Pakistan and by its warming relations with India. If India were to militarily retaliate against Pakistan for its continuing proxy war through surrogate terror groups, it will put the United States in an anomalous position of having to insulate its forces in Pakistan from the fighting and balance its ties with both rivals.
Washington's recent intense pressure on Pakistani military dictator Pervez Musharraf to clamp down on terrorist bands results from its recognition that the logic of events may compel India toward retaliating for the undeclared, one-sided war being pursued against it by Pakistan for years. With each additional step it takes to be ready for war, India is putting itself in a military position from which its leadership cannot back off.
When India may be forced to join the war, however, remains unclear. This is because the decision on when may not be made by New Delhi but be imposed on it by Pakistani terrorists carrying out more macabre killings in India.
The irony is that these terrorists, although linked to Pakistan's Inter-Services Intelligence agency, may not all be under the control of Mr. Musharraf and his Cabinet. But by failing to clamp down on such terrorists, Mr. Musharraf has made an open military confrontation with India more conceivable.
The latest crisis, triggered by the May 14 killing of 35 people, most of them the wives and children of Indian soldiers, is rooted in Mr. Musharraf's reneging on anti-terrorist pledges he made Jan. 12, a month after five Pakistani gunmen attempted to storm the Indian Parliament and kill the elected leadership.
Mr. Musharraf has quietly released in March and April most of the 2,000 militants he arrested in January as part of his much-publicized anti-terrorist cleanup. They include leaders of two Pakistani terrorist outfits tied to al-Qaida - Lashkar-e-Taiba, the largest Pakistani terrorist group, and Jaish-e-Muhammad.
He has also allowed banned terrorist outfits to regroup under new names and run publications. In fact, in the run-up to the recent sham referendum he held on his self-declared presidency, he mollycoddled Islamists in an effort to buy their support, freeing from custody some important extremists.
The probability of Indian military counteraction has also been increased by the failure of Indian diplomatic and economic sanctions against Pakistan to yield results and the credibility problem faced by Prime Minister Atal Bihari Vajpayee's government.
After terrorists attacked the Indian Kashmir legislature in October, Mr. Vajpayee warned President Bush in a letter that India would lose its patience if there were another major attack by a Pakistani militant group. But when the Indian parliament was attacked in December, Mr. Vajpayee drew a new line in the sand even as he exercised an important military option - mobilizing Indian forces on land and at sea for possible war.
More than five months later, yet another terrorist attack has forced Mr. Vajpayee to again vow retaliation. Pakistan's reluctance to match its anti-terrorism promises with deeds has paralleled India's reluctance so far to match its reprisal threats with action. But now the danger of open war has heightened because Mr. Vajpayee risks wrecking his credibility if he fails to carry through on his third threat of retaliation. In interstate relations, a threat to use force can achieve the same results as actually employing force, but only if the country concerned is prepared to carry through on that threat. The threat to use force has to be credible in the eyes of the adversary.
But not only has Mr. Musharraf so far failed to deliver on his anti-terrorist pledges despite India's threat of war, he has also mocked that the Indians want his help to rescue their troops along the border from being seared by the intense heat.
Given this perilous situation, only one development can avert an Indian military riposte: if the United States and its Western allies can induce Mr. Musharraf to begin fulfilling his Jan. 12 anti-terrorism pledge.
With Western interlocutors already delivering blunt messages to him, Mr. Musharraf can expect international pressure to mount in the coming days as British Foreign Secretary Jack Straw and U.S. Deputy Secretary of State Richard Armitage visit the subcontinent.
A genuine crackdown by Mr. Musharraf on Pakistani terrorist networks could dramatically disperse the war clouds even at this late stage.
Brahma Chellaney is a professor of strategic studies at the privately funded Center for Policy Research in New Delhi.