The massive flooding in Pakistan, which has killed more than 1,500 and displaced millions, is more than a humanitarian tragedy. It is a crucial test of competence and legitimacy for the government of Asif Ali Zardari. Unfortunately, the government is failing that test. The usual level of ineptitude and corruption that characterizes Pakistan’s political system—an annoyance in normal times—now provokes widespread public anger as desperately needed aid is painfully slow to arrive in hard-struck regions.

One should not underestimate how a government’s failure to respond adequately to a natural disaster can fatally erode popular support for a regime. A key catalyst for the fall of Nicaraguan dictator Anastasio Somoza to the Sandinista revolution in 1979 was the corrupt and inefficient response to the earthquake that devastated the country in 1972. In his book Inevitable Revolutions, Cornell University historian Walter La Feber notes that The Nicaraguan National Guard failed to maintain order in the aftermath, with soldiers often involved in widespread looting. Even worse, the government diverted and sold on the black market medical and relief supplies meant for hard-hit communities.

Before that episode, Somoza’s power seemed secure, and the Marxist Sandinista National Liberation front was an ineffectual fringe group. That all changed dramatically in the years following the earthquake. Zardari runs a similar risk today. Already, Taliban forces and other militants are moving far more effectively than the government to help victims of the flooding. That development could have very serious political implications.

Adverse political change in Nicaragua was never as important to the United States as the administrations of Ronald Reagan and George H.W. Bush seemed to believe. But the weakening of the Zardari government in Pakistan would be a major problem for Washington. At a minimum, it would complicate the U.S. military/nation-building mission in neighboring Afghanistan (ill-advised as that adventure might be). Even if the United States were not foolishly mucking about in Afghanistan, though, the emergence of a radical government in Islamabad—or Pakistan’s descent into chaotic, failed-state status—would be a relevant security issue for Washington. Nicaragua did not have nuclear weapons. Pakistan does, and the security of that arsenal is a matter of obvious concern.

U.S. leaders better hope that the Zardari government belatedly gets its act together regarding the flood relief effort. The possible political and strategic consequences if it does not are unpleasant to contemplate.