The scenes of hundreds of dead Taliban soldiers outside the fortress in Mazar-e-Sharif last week showed the brutality of US power. US warplanes bombed the fortress, killing around 400. Then the US allies in the Northern Alliance scavenged from the dead bodies.
This is what the greatest military power in the world does. In Iraq it killed 100,000 civilians and conscripts in 1991. Its bombing raids in 1998 and sanctions have killed half a million children.
Its military force backs up the economic devastation US corporations deliver to the poor across the world. And some of the most rabid in the US establishment are after more power. Leading US foreign policy adviser Zbigniew Brzezinski argues for a world where the US acts to preserve 'its unique global power'.
His strategy is to 'prevent collusion and maintain security dependence among the vassals, to keep tributaries pliant and protected, and to keep the barbarians from coming together'. It's not surprising many people feel that the US is all powerful, that it can march across the world imposing its interests without opposition. The US is the biggest military power in the world. It accounts for over a third of global military spending.
US president George Bush wants to further increase US military power through the 'Son of Star Wars' missile system that would back up US forces intervening anywhere in the world. But the US has not been able to simply impose its will unchallenged. It emerged as the lone superpower at the end of the Cold War, but in a much more unstable world.
The rigid division of the world during the Cold War went. But this has meant 'hot wars' breaking out as regional powers assert themselves militarily. The US maintains its global reach through a network of political and military alliances with various countries. There are tensions inside this network. The US faces what it calls 'rogue states' that don't accept the US dictating to the rest of the world.
Saddam Hussein in Iraq, installed by the CIA, was until 1990 a client of the US. He stepped out of line by invading Kuwait, a friend of the US. Iraq became one of the leading 'rogue states' that the US had to punish with bombing raids and is threatening to target again.
Similarly Serbian president Slobodan Milosevic was a man the West could do business with until he too stepped out of line in Kosovo in 1999. The US again reacted to this challenge through bombing raids, this time carried out through NATO.
The US also has to contend with rival powers such as Russia and China. Russia is a much weaker competitor for the US since the collapse of its economy. But it still has the world's second most powerful army and a massive nuclear arsenal.
Tensions between China and the US have already emerged over Taiwan, a key strategic ally for the US, and after the downing of a US spyplane earlier this year. Some leading figures in the US establishment also fear that China could pose a serious economic threat to the US if it can sustain its high growth rates of the last decade.
The US is trying to maintain its global position at a time when its economic position is weaker than during the Cold War. It is still the world's single biggest economy. But it is falling back from the dominant role it has played since the Second World War. At its height 50 years ago it accounted for 50 percent of world output. Today that figure is around 25 percent.
It is still able to dominate economically partly because its rivals have been in a crisis. Now it too faces an economic recession. One sign of the depth of the crisis is US multinational Enron filing for bankruptcy last week after the biggest share collapse in corporate history. The Japanese economy has been stagnating, but it is still the second largest economy in the world and a major competitor for the US. The US also has to compete with the economies in the European Union, which combined equal US output.
The US dominates economic institutions such as the World Bank, IMF and World Trade Organisation (WTO). But it does not always get its own way. There have been heated battles between the US, the European Union and Japan over who benefits from trade rules decided on by the WTO.
This has been posed in terms of US trade wars with Europe over bananas. But it may lead to conflicts over more important commodities, such as steel. It is precisely because the US has not been able to assert its dominance across the world that it is drawn into more military conflicts. In recent wars the US's greater military strength has secured it victories in Iraq and Kosovo.
But firepower alone didn't beat Saddam Hussein and Slobodan Milosevic. They both headed corrupt and repressive regimes that did not have strong support amongst their people. Milosevic had faced ten years of a rising movement against his rule. Saddam had carried out vicious attacks on his own people and had attacked Iran, a symbol of opposition to US power in the Middle East.
The US bombs angered the people of both countries. But the mass of the people did not rise up to defend those regimes. Iraq could have beaten the US if Saddam Hussein had appealed to wider forces to take up its fight. This would have meant calling on the poor in countries such as Egypt, a key US ally, to rise up and overthrow their corrupt rulers. But Saddam refused to unleash forces that could have turned round to oust him. This meant a straight fight between the conscripts Saddam Hussein could muster, and the power of US forces and daily pounding from bombing raids. It is no surprise that the US won the battle.
When the US picked a fight where its enemy had popular support, it faced far stronger opposition. In Vietnam the US faced a peasant guerrilla army that was struggling for national liberation. That army had been schooled in the fights against its colonial oppressors, France and Japan.
The Vietnamese were determined to drive the US out as well. This meant the US took on the whole population-not just the guerrillas. The troops could carry out an attack on US soldiers and disappear into the villages where local people would hide them.
The US increased its brutality against Vietnamese civilians to try to break their resistance. US planes dropped over eight million tonnes of bombs on Vietnam. But the Vietnamese fought on. This resistance became an inspiration to those suffering oppression across the world. A small peasant army could beat a mighty economic and military power. In the US itself it provoked a powerful anti-war movement that demanded the government end the war.
Since 1975 the US ruling class has been haunted by the 'Vietnam syndrome'. It has not wanted to commit US forces to what becomes seen as a pointless war with high US casualties. So even a small country, Nicaragua, was able to stand up to brutal US aggression for ten years. The US relied on Contra death squads and did not feel able to deploy its own uniformed troops directly.
And it made one botched effort to overthrow the Cuban regime 40 years ago, but has not been able to go further than an economic blockade since then. The US's most militarised ally, Israel, invaded Lebanon in 1982, but has been forced out of the country by popular resistance. US rulers still fear that they could face a popular movement where superior military power would not be enough to win.
The war in Afghanistan has already opened up tensions among the mass of people in Saudi Arabia, Egypt and other countries. A popular revolt against those corrupt regimes could become a beacon to millions of others living in similar repressive regimes across the region. And such a movement in one of the advanced capitalist countries would provide an even deeper challenge to US imperialism.
The US may be the superior economic and military power in the world. But it sits at the top of a system with rival competitors eager for their share of power, and that provokes seething discontent amongst the mass of people across the world.
That is a force that can break US imperialism, the number one defender of global capitalist interests.