After 20 years of daily battles and huge investment in the Afghan army, the US withdrew from Afghanistan militarily and politically defeated, in a way unfit for the only superpower in the world. After 20 years of hit-and-run warfare and hiding in the caves of Tora Bora, infiltrating remote civilian neighbourhoods and often resorting to heinous terrorist acts, the Taliban militant group has returned to the Afghan capital, Kabul, ecstatic with a victory similar to the one many of its fighters enjoyed in the 1980s over the Soviet Union. The US withdrawal from Afghanistan was hasty, blundering and catastrophic in its implications for America's image and reputation at a moment in which there are rising doubts about its ability to lead the world in the 21st century. Washington is currently waking up to a heated political debate in its think tanks, academies and corridors of power about how America lost Afghanistan. Was the decision to withdraw carefully and deliberately planned or was it a disastrous strategic mistake that US President Joe Biden will have to pay for in the next election, if he decides to run again in 2024? How did the only superpower in the world emerge defeated by terrorist militias that seem to come from the Dark Ages? These questions will remain unresolved for a long time. But the most important question for Arab Gulf states, which are located only 2,000km away from Afghanistan, is: “What are the implications of the US withdrawal from Afghanistan on the security of the Gulf?” Is the US's withdrawal from Afghanistan simply a prelude to a long-term plan for a gradual military withdrawal from the Arab Gulf, too? What are the choices facing the Arab Gulf countries? The Arab Gulf states are not without options. They are sensitive to the mood in the US, which is partial towards a withdrawal from foreign conflicts, and well attuned to what is going on behind the scenes in Washington, where there is talk that the Arab Gulf is not as vital a region as it was in the past. These countries have many choices, perhaps the first and the most important of which is the possibility of developing their self-defence capabilities and avoiding the mistake of building a dysfunctional army, like the one in Afghanistan, which fell in its first real confrontation with the Taliban without US aid. The UAE's experience in building an army capable of both combat and deterrence is important in this context, and it is at the forefront in the region in that regard. The F-35 aircraft deal with the US is only an early step in this future national defence project. In addition to developing self-defence capabilities, it is important for the Gulf states to prioritise the strengthening of Gulf military co-operation and connect the Gulf’s armies to one another operationally and institutionally. A unified Gulf army has become more urgent than ever. There is no doubt that defence coordination is in much need of a strategic and political decision that enhances and accelerates the paths of reconciliation and strengthens the path of Gulf security co-operation. But the security of the Arab Gulf is not only the responsibility of the Gulf states. It has always had an international dimension, due to its strategic location and oil wealth. The international presence in the Gulf security equation has become necessary after the recent developments in Afghanistan and Washington's complacency with respect to Iran's violations, as well as the escalation of sabotage activity around the Strait of Hormuz. Any American absence must be compensated by a British, French and European military presence, as well as a Chinese, Indian and South Korean military presence, by virtue of the region’s value to the East. The internationalisation of Gulf security is one option for the post-American Gulf era. Whatever the case is, the hasty US withdrawal from Afghanistan, the strong return of the Taliban to the Afghan capital and the escalation of the Iranian threat indicate that the Gulf security equation will be very different this century compared to the last. The Gulf is on the verge of huge security and military transformations, perhaps even the largest since 1971, when the US assumed responsibility for its security and turned it into an “American Gulf”, in a strategic sense. It may not be the same during the next five decades. The US was previously defeated in Vietnam and quickly regained its global leadership role especially after the collapse of the Soviet Union. Today, it has withdrawn from Afghanistan with a painful defeat, and its project in Iraq is also faltering. In each of these cases, Washington committed horrendous errors in its calculations of its own strength and that of its opponents and enemies. The US will preserve what remains of its military, political and financial power in the post-Afghanistan era, but it is certain that the American public mood has become strongly opposed to foreign adventures, and the world has entered a post-American era where Washington cannot and does not want to manage the world affairs alone. This is clearly embodied in “Trumpism”, the doctrine of former president Donald Trump, and the subsequent “Bidenism”, both of which are rooted in the logic that the domestic is more important than the foreign. The US has the right to take the decision that best suits its national interest, but that decision will not be bound within America. The fatal cost of American mistakes is not paid by the US, but its friends and partners, such as Afghanistan. The US's mistakes have been catastrophic recently, and it will be necessary for the Gulf states to learn lessons from them. It is time to reduce dependence on Washington in the strategic realm. Trust in the US also needs to be reviewed, and a deep and fundamental reconsideration is needed. Even the old association with the US that suited the circumstances of the 20th century may not fit those of the 21st century, nor may it fit the circumstances of the emergence of the Gulf as a rising force in the Arab region. <i>Dr Abdulkhaleq Abdulla is a UAE-based retired professor of political science</i>