From bad to worse:

On one side of the border now stands Gen. Pervaiz Musharraf, an aggrieved ex-commando who strikes boldly. The coup he led Wednesday against Pakistan's democratically elected government is only his latest attempt to force the action in South Asia: Last spring, he authored a failed, embarrassing incursion against India in the mountains of Kashmir. While no neophyte, the Pakistani army chief of staff appears to know little about world politics, yet is convinced that he is central to his country's destiny.

On the other side of the border is India's newly emboldened political force, the Hindu nationalist Bharatiya Janata Party (BJP). Fresh from an electoral victory forged in part from its religious-toned pursuit of great-power status for India, the BJP's leaders are unifying the country with a claim that only they are strong enough to defend India from Pakistan's nefarious designs.

On both sides of the border are fervently nationalistic teams of nuclear and missile scientists who have already assembled small stores of nuclear weapons components and fissile material for up to several dozen bombs. Each side announced successful nuclear weapons tests in May 1998, and while doubts remain about how much technical progress these rival Manhattan Projects have made, each certainly can crudely deliver a nuclear bomb to the other's soil.

The risk of such a cataclysm is now greater than ever. Musharraf's coup and India's expanding embrace of Hindu nationalist leadership are mutually reinforcing events. They loosen restraints on the subcontinent's nuclear arms race, providing each side with confirmation of its worst fears about the other and ample rationale for more rapid weapons development and deployment.

Just eight months ago, the subcontinent rejoiced when Indian Prime Minister Atal Bihari Vajpayee staged a Nixon-to-China bus trip to the Pakistani city of Lahore. Now hopes of reconciliation lie in tatters. The deposed Pakistani prime minister, Nawaz Sharif, was Vajpayee's partner in that quixotic, back-channel peace effort.

American influence in the region, weak to begin with, is in free fall. Washington's argument that Pakistan should pressure India diplomatically by capping its nuclear program and signing the Comprehensive Test Ban Treaty now echoes hollowly, after the U.S. Senate's emphatic rejection of the pact. The Pakistani coup and the Senate's vote--defiant, inward turns in capitals half a world apart--are seen abroad as related events that hasten the prospect of the world's first nuclear detonation in anger since Nagasaki.

That threat, while hardly imminent, lies in the coming interaction between Pakistan's now openly militaristic government and India's governing Hindu nationalists.

As Musharraf staged his takeover, tens of millions of middle-class Indians with satellite hookups could toggle between scenes of Pakistani soldiers clambering over the walls of government compounds in Islamabad and the televised installation of their own theatrical BJP-led coalition in New Delhi. With the coup only hours old, the Hindu leaders described Musharraf's intentions darkly and placed their armed forces on immediate alert.

That interplay forecasts a larger pattern. The main political narrative in India today is the BJP's bid to succeed the discredited, fractured Congress Party as the country's source of national unity. Developing a nuclear doctrine, testing nuclear weapons and rattling sabers along the Kashmir border have been key elements of this domestic political calculus.

Musharraf's coup propels the BJP's strategy forward. His takeover ends the recent pretense of unresolved tension between civilian and military goals in Pakistan's posture toward India. Islamabad's new face of aggression makes it easier for the BJP to pursue openly--and in defiance of outside pressure, if necessary--the country's announced rough-draft strategy of a nuclear triad, meaning the development of nuclear weapons that can be delivered via missiles, aircraft and submarines.

Alarms are already sounding in the hushed offices of security analysts and nonproliferation specialists. After Musharraf's takeover, "The BJP is basically going to give a blank check to the [nuclear] scientists," says Sumit Ganguly, a visiting fellow at Stanford University's Center for International Security and Cooperation, and a specialist on Indian nuclear policy. "They're going to say to the scientists, 'Go ahead with your missile program. Start thinking about how to miniaturize [nuclear] weapons and put them on warheads.' "

The pace of Indian deployment will remain slow; the country's military scientists face significant technical problems. But any acceleration will spook and spur on the Pakistanis. On that side of the border, Musharraf's track record does not inspire confidence. After a year as army chief, he has provided few signs that he will use the military's power responsibly.

"The personality of the army chief is a non-trivial matter," as Michael Krepon, a close student of the Pakistani army at the Henry L. Stimson Center, puts it wryly. Krepon spent time with Musharraf during the last year and finds him "not terrible thoughtful. He's a guy who is not all that bright. But he's highly decorated. Doesn't know much about the world . . . . His sense of international politics and strategy were on display in Kargil," the site of his army's springtime disaster in Kashmir.

Yet, almost unimaginably, some Pentagon officials and other policymakers in the United States are nostalgic for an army leader in Pakistan. They remember the salad days of partnership during the anti-Soviet war in Afghanistan, and leap to the conclusion that Musharraf is like Pakistani generals of old--a man with whom they can do business. What they are overlooking is that Musharraf belongs to a generation of generals who rose to power during the 1990s, when U.S. sanctions enforced the generals' physical, intellectual and ideological isolation. Nor do the U.S. and Pakistani militaries today have any meaningful agenda to bind them together--not to mention that such interaction is heavily constrained by U.S. law.

After several days of silence, Musharraf has again delayed a major political speech that would outline his plans. His only appearance before his countrymen to date--a four-minute speech on national television immediately after the coup--was oddly devoid of political or foreign policy goals. Instead, he recounted personal grievance--how the prime minister had tried to send him into exile by diverting his plane, but "thanks be to God," he had managed to land and stage his coup. He complained that Sharif had insulted the Pakistani army, "the last remaining viable institution in which all of you take so much pride and look up to at all times" (a claim that may underestimate the popularity of the national cricket team).

Yet having taken power and pledged national salvation, Musharraf has now placed the army's most vital interest--itself--at grave risk.

After more than a decade of mostly standing aside from politics, the army must now deliver on the credibility Musharraf bragged about awkwardly on Wednesday. That means tackling intractable problems such as corruption, poverty and sectarian violence. The army is poorly equipped for these challenges, but even to attempt a credible reconstruction of civil society, it needs two things: foreign money and breathing space from serious conflict with India. Neither will be easily acquired.

Reacting to Musharraf's takeover, Pakistan's elite sounded astonishingly exhausted--even disgusted--by its 15-year, hard-won experiment with constitutional democracy. Sharif's attempts to smash centers of opposition to his rule--the press, the Supreme Court, the National Assembly--have left little but a shell of constitutionalism. Former prime minister Benazir Bhutto is discredited, in exile in London from a corruption indictment. Even liberal newspaper editors openly invite Musharraf to rule for a prolonged period.

This appetite for army-led stability is delusional. Not only is the army unlikely to "save" Pakistan, its attempts to assert itself threaten to accelerate a cycle of nuclear risk on the subcontinent. In the end, the United States, India and Pakistan all share a profound interest in the development--however difficult, however gradual--of a deeply rooted, democratic civic society in Pakistan. This is what India's Vajpayee, perhaps alone in the BJP's leadership, understood when he made his historic bus trip to Lahore. What a long, long time ago that February day now seems.

Steve Coll, managing editor of The Washington Post, served as the newspaper's South Asia bureau chief from 1989 to 1992, based in New Delhi. He is the author of "On the Grand Trunk Road: A Journey Into South Asia" (Times Books).