With the overthrow of Prime Minister Nawaz Sharif, the military is now in total control of Pakistan's nuclear-capable missiles, aircraft and what are believed to be up to 25 atomic weapons at a time tensions with India remain high over the disputed northern Kashmir region.
"Pakistan is a troubled country, and centrifugal forces within it are likely to grow as a result of this coup," said Michael Krepon, a South Asia expert at the Henry L. Stimson Center, a Washington-based policy research institute. "There is a real question about whether divisions will grow within the army leadership, and that has the most serious implications for nuclear command and control."
Zia Mian, a Pakistani academic at Princeton University, warned: "Militaries are paid to think only about fighting and winning wars."
India and Pakistan came to the verge of war this past summer after Pakistani-backed Islamic militants crossed into the Indian-controlled side of Kashmir and seized strategic high ground. India launched a major drive to dislodge them, igniting clashes along the frontier with Pakistani regular forces and stoking fears the confrontation could go nuclear. It took President Clinton's personal intervention with Sharif to compel a Pakistani withdrawal.
There appears to be little the United States can do now. Experts say the best course is to join with its allies to pressure the architect of the takeover, the army chief of staff, Gen. Pervaiz Musharraf, to adhere to a constitutional requirement to hold elections within 90 days.
"We would obviously seek the earliest possible restoration of democracy in Pakistan," State Department spokesman James P. Rubin said.
But experts said the United States appeared to have little leverage with the Pakistani military. Washington halted arms sales to Islamabad under sanctions imposed after the 1998 nuclear tests.
These experts point out that past sanctions did not stop Pakistan's atomic weapons development program or its alleged cooperation on missile and nuclear technology with China. Furthermore, tightening the 1998 sanctions could fuel instability in Pakistan by exacerbating its current dire economic crisis.
The economic crisis and the pullback from Kashmir, a personal humiliation for Musharraf and his commanders, are widely believed to have contributed to the army's decision to topple Sharif.
Pakistan also is mired in high-level corruption: Sharif himself was accused of wrongdoing. The country is beset by political turmoil and strife between its Sunni Muslims, the vast majority of its 140 million people, and members of the minority Shiite branch of Islam. A large number of leading Shiites have been killed in sectarian attacks in the last month.
In his first TV address to the nation after the coup, Musharraf insisted that the takeover was forced by Sharif's failure to address the country's problems and what he said was an attempt to politicize the armed forces by replacing him only a few weeks after confirming him in the chief of staff post until April 2000.
"The government tried to politicize the army, destabilize it, and had to create dissension within its ranks," Musharraf said.