Islamabad, Pakistan ? The floods tearing through Pakistan’s breadbasket have further weakened this already unstable country, inflicting more economic pain on its people and threatening a key pillar of the U.S.-led war against Islamist militants — who stand to gain from the misery. For now attention is focused on meeting the immediate needs of the millions of people affected by the still-spreading disaster.

A Pakistani girl flood victim carries drinking water Saturday across a damaged road at Baseera, Punjab Province, Pakistan. About 150,000 Pakistanis were forced to move to higher ground as floodwaters from a freshly swollen Indus River submerged dozens more towns and villages in the south, a government spokesman said.

Yet the floods — described as Pakistan’s worst-ever natural calamity — are already complicating U.S. goals of defeating al-Qaida and the Taliban and stabilizing neighboring Afghanistan.

With international aid still not coming in fast enough, public anger at the government is likely to swell as millions face months or even years of destitution, risking turmoil just as Washington and the region needs stability in the nuclear-armed state.

“The stakes are very, very high,” said Sen. John Kerry, who visited this week. “We are particularly anxious, all of us, to see the country get back on track.”

The floods began in the northwest, hitting the Swat Valley and areas close to the main city of Peshawar, before moving down the country by way of the mighty River Indus, devastating millions of acres of crops in the country’s “breadbasket” in Punjab and the Sindh.

About one-fifth of the country — a chunk of land about the size of Italy — has been affected.

At least 8 million people are in need of water, shelter or other emergency assistance, making the disaster larger than Pakistan’s last two humanitarian crises, the exodus from Swat last year amid an army offensive against the Taliban and the 2005 Kashmir earthquake.

The country was already blighted by soaring food inflation, chronic unemployment, crumbling schools and hospitals and rolling power cuts across the country. About 60 percent of its 170 million get by on less than $2 a day. Last year, the economy was kept afloat by a $7.6 billion loan from the International Monetary Fund.

The floods are predicted to shave at least 1 percent of Pakistan’s gross national product this year, in large part because of their effect on the country’s agricultural sector, which accounts for about 20 percent of the economy. The country’s textile industry is also expected to suffer because of damage to cotton crops.

Already, the prices of vegetables, meat and dairy products have risen sharply across the country.

“No country is set up to deal with this scale of potential loss in its agricultural sector,” said Anthony Cordesman from the Center for Strategic and International Studies.

Looking after the victims is a huge task that would strain even the best government and international agencies. Authorities must also start thinking ahead to rebuilding homes and infrastructure such as roads and bridges, and getting people — most of them poor farmers — back to work.

“The government now has to tackle two things at the same time, the macroeconomic stability and the reconstruction effort,” said Juan Miranda, the Asian Development Bank’s director general for Central and West Asia. “I don’t think any of us can envy the task ahead of them.”

Historical precedents are hard to find for a disaster on this scale, but Pakistan has proved resilient in the past when faced with crisis. With committed government and the full support of the international community, some of the worst-case scenarios may not play out.