Are Pakistani nukes safe?

"I'm confident that we can make sure that Pakistan's nuclear arsenal is secure," Mr. Obama said Wednesday, "primarily, initially, because the Pakistani Army, I think, recognizes the hazards of those weapons falling into the wrong hands." He added: "We've got strong military-to-military consultation and cooperation."

But that cooperation, according to officials who would not speak for attribution because of the sensitivity surrounding the exchanges between Washington and Islamabad, has been sharply limited when the subject has turned to the vulnerabilities in the Pakistani nuclear infrastructure. The Obama administration inherited from President Bush a multiyear, $100 million secret American program to help Pakistan build stronger physical protections around some of those facilities, and to train Pakistanis in nuclear security.

But much of that effort has now petered out, and American officials have never been permitted to see how much of the money was spent, the facilities where the weapons are kept or even a tally of how many Pakistan has produced. The facility Pakistan was supposed to build to conduct its own training exercises is running years behind schedule.