About 300 vehicles and containers loaded with U.S. and nato supplies were destroyed or damaged in three separate attacks in Pakistan this week. The threat to the primary supply chain into Afghanistan is growing, and the United States has few other options.

On December 8, in an early-morning attack on a truck terminal in Peshawar, Islamist terrorists set fire to nearly 100 trucks and trailers, destroying U.S. and nato supplies bound for Afghanistan. A day earlier, a similar attack was even more destructive—the biggest and boldest such attack yet. About 250 militants armed with grenades, automatic weapons and Molotov cocktails attacked two other nearby truck terminals in the middle of the night. The guards were overwhelmed and some 200 trucks (including Humvees), trailers and containers where burned, destroying food, battle tanks and armored personnel carriers. Then, on Thursday, dozens of armed militants set fire to another terminal, destroying several trucks and containers.

The intent in these attacks was clearly to stop U.S. supplies from getting to Afghanistan. Attacks on U.S. supply lines through Pakistan are nothing new. Previous attacks, however, have concentrated on convoys moving through the Khyber Pass and have been largely for the purpose of stealing vehicles and equipment. In the Peshawar attacks, however, the terrorists purposed only to destroy the vehicles and their contents. This may indicate the Islamists have taken on a more offensive stance against coalition forces.

This threat to its supply lines is no small issue for the U.S. The vast majority—80 to 90 percent—of supplies for coalition forces in Afghanistan currently pass through Pakistan. Those supplies include fuel that is refined in Pakistan as well as food, vehicles, ammunition and other materials that are shipped to the port of Karachi. Truck convoys have to pass through hostile territory to get all these supplies to Afghanistan. Because of the high incidence of attacks in the Khyber Pass, Pakistani security has been stepped up in this area. As a result, the militants are now exploiting weaknesses in a different part of the supply chain: truck terminals.

As such attacks increase, the U.S. has no good alternatives for getting the massive amount of supplies it needs into Afghanistan. Northern routes are longer, more difficult, largely landlocked—and under Russian influence. Airlifts are not sufficient, and they require friendly airbases in the region.

At the same time, the U.S. has few resources to spare to fight the militants that are attacking its supply lines through Pakistan. U.S. and nato forces are stretched thin; Pakistani forces don’t seem to be able to do more; and local guards are unreliable. And, as soon as one area is secured, the terrorists can focus on a different link in the supply chain. Moreover, Stratfor reports (December 8),

With India and Pakistan preparing for the fallout from the November 26 attacks in Mumbai, it is not even certain that Pakistan will be willing to keep deploying valuable troops to protect U.S. and nato supply chains into Afghanistan. This uncertainty, along with the fact that the entire supply chain from Karachi to the Afghan-Pakistani border is also vulnerable to attack, makes any meaningful defense of supply shipments unlikely.

This growing threat to the U.S.’s war effort in Afghanistan comes as America seeks to boost the number of its forces there. It also comes at a time when Pakistan’s government and military is becoming increasingly unreliable. Islamabad’s evident lack of control of Islamist militants within Pakistan compromises its ability to assist Washington. And, as pressure mounts for India to take military action against Pakistani militants, U.S. supply lines may become the last thing Islamabad is concerned about protecting.

The U.S. is failing to make headway against the Taliban in the hostile terrain of Afghanistan as it is. Should things spiral out of control in Pakistan, that battle could become a whole lot harder.

To learn why America’s war efforts are failing and how this was prophesied in the Bible, read “America Has Won Its Last War.”