Is this the end of the American era? Today, the United States scrambles to evacuate its citizens stuck in Afghanistan, as its rivals take advantage of 'America's Great Retreat'.

After twenty years of war, the United States has been forced into a sudden and chaotic retreat from Afghanistan. In less than a week, Taliban fighters have overwhelmed the country and stormed the capital, Kabul.

Many compare the scenes at the airport to the fall of Saigon7,000 people fled the Vietnamese city in the largest helicopter evacuation in history, ending 19 years and 5 months of US military involvement in Vietnam. in 1975, when people climbed from roofs into helicopters as the city fell to the North Vietnamese army. The US exit from Vietnam is sometimes called America's greatest defeat.

But some think this is much worse.

President Joe Biden predicted a smooth handover of power to Afghan president Ashraf Ghani and an orderly withdrawal. In an embarrassing turnaround, he now says the chaos was "inevitable", whilst Ghani has fled to the United Arab Emirates.

Biden refuses to admit defeat. In response to the September 11 attacksThe coordinated hijacking of four US planes on 11 September 2001 claimed 2,977 lives and was the deadliest terrorist attack in US history., the US invaded Afghanistan to capture or kill the Al-QaedaThe terrorist organisation was set up in 1988 by Osama bin Laden and other Arab volunteers fighting in the Soviet-Afghan War. leadership. That mission, says Biden, was a "success".

But the war was also supposed to bring democracy to Afghanistan and defend human rights. The Taliban says democracy will now be replaced by their interpretation of Sharia lawA legal system based on Islamic teaching. Gay Afghans and Afghan women say the Taliban's strict reading of Sharia is not compatible with their human rights., which denies education to women and criminalises homosexuality.

In the last 20 years, 47,000 civilians have been killed, along with 69,000 Afghan military personnel and 2,500 US soldiers. Over $2tn has been spent and the bill continues to rise as the US cares for over 20,000 injured veterans.

It may seem incredible that the world's most powerful army could lose to a ragtag militia of 60,000 poorly-armed fighters. But this is not the first time a global superpower has been humbled and humiliated in its attempt to control Afghanistan.

Gone for good?

In the 19th Century, Britain fought Russia in a great gameAlso known as the "tournament of shadows" in Russia. The First Anglo-Afghan War (1839 - 1842) was followed by a second (1878 - 1880) that Britain won, but with heavy casualties. for control of Central Asia. 16,000 people abandoned Kabul in 1842 in "the greatest disaster" for the British Empire. Only one European and a few Indians survived the Afghan attack.

In 1989, the Soviet UnionOfficially the Union of Soviet Socialist Republics (USSR). A powerful group of communist republics, the biggest being Russia, that existed from 1922 to 1991. lost a nine-year war to prop up a communist regime, earning Afghanistan's reputation as the "graveyard of empires". Two years later, the Soviet Union collapsed.

Some think future historians will see the Taliban's victory as the last chapter in the American era. It began with the liberation of Europe and East Asia in World War Two. Will it end at the airport in Kabul?

Russia hopes so. Its foreign minister says the West is "giving up" in Central Asia and that countries should think twice before looking to the US for help. As the flag is lowed over the US embassy, the Russian ambassador welcomes the new Taliban security forces, calling them "decent guys".

But if Russia hopes to fill the power vacuumA political situation where someone in power has lost control, creating space for new forces to take their place., it must compete with China. The Asian giant is already investing in Afghanistan as part of its global Belt and Road InitiativeChina aims to build a "new silk road" through Asia to boost trade and extend its economic and political influence.. Pakistan is another likely winner, with its close links to the Taliban.

So is this the end of the American era?

Some say yes, America's global influence is in decline. It has lost the longest war in its history and it will find it impossible to convince allies and voters that future wars will be worth the cost. Its failure to defend democracy and human rights in Afghanistan will convince many that it lacks the will or ability to do so. In the gap left by the US, other countries will take its place.

Others say this assessment is too simplistic. Wars in Afghanistan have always ended in failure, but there is more to global power than military supremacy. The world is still dominated by US culture and corporations, with the United States leading the way in science, biotechnology and space exploration. Its reputation has been damaged, but it can still show leadership by taking in Afghan refugees.