United States invasion of Afghanistan in the context of "Operation Enduring Freedom"

The war in Afghanistan was a prolonged armed conflict lasting from 2001 to 2021. It began with an invasion by a United States–led coalition under the name Operation Enduring Freedom in response to the September 11 attacks carried out by the Taliban-allied and Afghanistan-based al-Qaeda. The Taliban were expelled from major population centers by American-led forces supporting the anti-Taliban Northern Alliance, thus toppling the Taliban-ruled Islamic Emirate. Three years later, the American-sponsored Islamic Republic was established, but by then the Taliban, led by founder Mullah Omar, had reorganized and begun an insurgency against the Afghan government and coalition forces. The conflict ended almost twenty years later as the 2021 Taliban offensive reestablished the Islamic Emirate. It was the longest war in United States military history, surpassing the Vietnam War by six months.

Following the September 11 attacks, masterminded by al-Qaeda leader Osama bin Laden, American president George W. Bush demanded that the Taliban immediately extradite him to the United States and close down al-Qaeda's camps in Afghanistan; the Taliban refused and demanded evidence of bin Laden's guilt before offering to hand him over to a neutral country. The U.S. dismissed these offers and proceeded with the invasion. After expelling the Taliban and their allies, the American-led coalition remained in Afghanistan, forming the International Security Assistance Force (ISAF)—sanctioned by the United Nations—with the goal of creating a new democratic authority in the country that would prevent the Taliban from returning to power. A new Afghan Interim Administration was established, and international rebuilding efforts were launched. By 2003, the Taliban had reorganized and launched a widespread insurgency against the new Afghan government and coalition forces. Insurgents from the Taliban and other Islamist groups waged asymmetric warfare, fighting with guerrilla warfare in the countryside, suicide attacks

The Taliban, which also refers to itself by its state name, the Islamic Emirate of Afghanistan, is an Afghan political and militant organization with an ideology comprising elements of the Deobandi movement of Islamic fundamentalism and Pashtun nationalism. It ruled approximately 90% of Afghanistan from 1996 to 2001, before it was overthrown by an American-led invasion after the September 11 attacks carried out by the Taliban's ally al-Qaeda. Following a 20-year insurgency and the departure of coalition forces, the Taliban recaptured Kabul in August 2021, overthrowing the Islamic Republic, and now controls all of Afghanistan. The Taliban has been condemned for restricting human rights, including women's rights to work and have an education, and for the persecution of ethnic minorities. It is designated as a terrorist organization by several countries, and the Taliban government is largely unrecognized by the international community.

The Taliban emerged in 1994 as a prominent faction in the Second Afghan Civil War (1992–1996) and largely consisted of warlords from the Pashtun areas of eastern and southern Afghanistan. Under the leadership of Mullah Omar, the movement spread through most of Afghanistan, shifting power away from the Islamic State of Afghanistan, as well as other Mujahideen militants. The Taliban seized Kabul in 1996 and established the First Islamic Emirate of Afghanistan that was opposed by the Northern Alliance, which maintained international recognition as a continuation of the Islamic State.

The Northern Alliance, officially known as the National United Islamic Front for the Salvation of Afghanistan, was an Afghan military alliance of groups that operated between early 1992 and 2001 following the dissolution of the Soviet Union. It was formed by military leaders such as Ahmad Shah Massoud, Burhanuddin Rabbani, Abdul Rashid Dostum, Abdul Momim and Ali Mazari. It consisted mainly of ethnicities from northern Afghanistan, such as Tajiks, Uzbeks, Hazaras, and Turkmens, as opposed to the Pashtun-led Taliban. At that time, many non-Pashtun Northerners originally with the Republic of Afghanistan led by Mohammad Najibullah became disaffected with Pashtun Khalqist Afghan Army officers holding control over non-Pashtun militias in the North. The alliance's capture of Mazar-i-Sharif and more importantly the supplies kept there crippled the Afghan military and began the end of Najibullah's government. Following the collapse of Najibullah's government, the Alliance would fall with a second civil war breaking out. However, following the Taliban's takeover of Kabul and establishment of their Islamic Emirate of Afghanistan, the United Front was reassembled.

The Northern Alliance fought a defensive war against the Taliban regime. They received support from Iran, Russia, Tajikistan, Turkmenistan, the United States and Uzbekistan, while the Taliban were extensively backed by the Pakistan Army and Pakistan's Inter-Services Intelligence. By 2001, the Northern Alliance controlled less than 10% of the country, cornered in the north-east and based in Badakhshan province. The US invaded Afghanistan, providing support to Northern Alliance troops on the ground in a two-month war against the Taliban, which they won in December 2001. With the Taliban forced from control of the country, the Northern Alliance was dissolved as members and parties supported the new Afghan Interim Administration, with some members later becoming part of the Karzai administration.

The Islamic Emirate of Afghanistan (Pashto: د افغانستان اسلامي امارت, romanized: Da Afghānistān Islāmī Imārāt), retroactively referred to as the First Islamic Emirate of Afghanistan, was a totalitarian Islamic state led by the Taliban that ruled most of Afghanistan from 1996 to 2001. At its peak, the Taliban government controlled approximately 90% of the country, while remaining regions in the northeast were held by the Northern Alliance, which maintained broad international recognition as a continuation of the Islamic State of Afghanistan. The Taliban referred to the government as interim throughout the entire period of its existence, despite the strong and permanent role of Mullah Omar in the government.

After the September 11 attacks and subsequent declaration of a "war on terror" by the United States, international opposition to the regime drastically increased, with diplomatic recognition from the United Arab Emirates and Pakistan being rescinded. The Islamic Emirate ceased to exist on 7 December 2001 after being overthrown by the Northern Alliance, which had been bolstered by the ISAF coalition established after a U.S.-led invasion of the country two months prior. The Taliban continued to refer to itself as the Islamic Emirate of Afghanistan in official communications when it was out of power from 2001 to 2021.

The Islamic Republic of Afghanistan was a presidential republic in Afghanistan from 2004 to 2021. The state was established to replace the Afghan interim (2001–2002) and transitional (2002–2004) administrations, which were formed after the 2001 United States invasion of Afghanistan that had toppled the partially recognized Taliban-ruled Islamic Emirate of Afghanistan. However, on 15 August 2021, the country was recaptured by the Taliban, which marked the end of the 2001–2021 war, the longest war in US history. This led to the overthrow of the Islamic Republic, led by President Ashraf Ghani, and the reinstatement of the Islamic Emirate under the control of the Taliban, today the ruling government of Afghanistan. While the United Nations still recognizes the Islamic Republic as the legitimate government of Afghanistan, this toppled government controls no portion of the country. The US–Taliban deal, signed on 29 February 2020 in Qatar, was one of the critical events that caused the collapse of the Afghan National Security Forces (ANSF). Following the deal, the US dramatically reduced the number of air attacks and deprived the ANSF of a critical edge in fighting the Taliban insurgency, leading to the Taliban takeover of Kabul.

Following the September 11 attacks, the United States and several allies invaded Afghanistan, overthrowing the Taliban's first government (which had limited recognition) in support of the opposition Northern Alliance. Afterwards, a transitional government was formed under the leadership of Hamid Karzai. After the 2003 loya jirga, a unitary presidential Islamic republic was proclaimed under a new constitution, and Karzai was elected for a full term as president. Meanwhile, the US-led international coalition helped maintain internal security, gradually transferring the burden of defense to the Afghan Armed Forces after 2013–14.

The 2021 Taliban offensive was a military offensive by the Taliban insurgent group and allied militants that led to the fall of the Islamic Republic of Afghanistan and the end of the nearly 20-year War in Afghanistan that had begun following the United States invasion of the country. The Taliban victory had widespread domestic and international ramifications regarding human rights and proliferation of terrorism. The offensive included a continuation of the bottom-up succession of negotiated or paid surrenders to the Taliban from the village level upwards that started following the February 2020 US–Taliban deal.

The offensive began on 1 May 2021, coinciding with the withdrawal of the United States's 2,500 troops in Afghanistan, and those belonging to other international allies. Large numbers of armed civilians, including women, volunteered with the Afghan Army in defense, while some former warlords, notably Ismail Khan, were also recruited. Despite this, the Taliban managed to make significant territorial gains in the countryside, increasing the number of districts it controlled from 73 to 223 in the first three months of the offensive. On 6 August, the Taliban launched an assault on the provincial capitals, with most of the towns surrendering without a fight, culminating with victories in weeks-long battles of major cities Herat, Kandahar and Lashkargah on 13 August. On 15 August, President Ashraf Ghani fled the country and the Taliban captured the Afghan capital Kabul with only sporadic resistance; thus, the Islamic Republic of Afghanistan's government fell, resulting in the de facto takeover of the country and the reinstatement of the Islamic Emirate of Afghanistan. The speed of the Taliban's takeover came as a surprise to many, including the governments of the United States and their allies, Russia and the Taliban themselves.

The International Security Assistance Force (ISAF) was a multinational military mission in Afghanistan from 2001 to 2014. It was established by United Nations Security Council (UNSC) Resolution 1386 pursuant to the Bonn Agreement, which outlined the creation of a permanent Afghan government following the United States invasion in October 2001. ISAF's primary goal was to train the Afghan National Security Forces (ANSF) and assist Afghanistan in rebuilding key government institutions; it gradually took part in the broader war in Afghanistan against the Taliban insurgency.

ISAF's initial mandate was to secure the Afghan capital of Kabul and its surrounding area against opposition forces to facilitate the formation of the Afghan Transitional Administration headed by Hamid Karzai. In 2003, NATO took command of the mission at the request of the UN and Afghan government, marking its first deployment outside Europe and North America. Shortly thereafter, the UN Security Council expanded ISAF's mission to provide and maintain security beyond the capital region. ISAF incrementally broadened its operations in four stages, and by 2006 took responsibility for the entire country; ISAF subsequently engaged in more intensive combat in southern and eastern Afghanistan.

Reconstruction in Afghanistan refers to the efforts to improve Afghanistan's governance as well as physical buildings and infrastructure following the overthrow of the First Islamic Emirate of Afghanistan by the United States. These efforts involved various groups including supranational organizations, the Afghan government, the US government and other foreign governments, and civilians. These efforts also include training civil administrators, improving essential services and public safety, supporting civil society and self-determination, and promoting the rule of law and economic development.

The Islamic National Army of Afghanistan (Pashto: د افغانستان اسلامي ملي اردو Də Afġānistān Islāmi Mili Urdu, Dari: اردو ملی اسلامی افغانستان Urdu-yi Milī-yi Islāmī-yi Afğānistān), also referred to as the Islamic Emirate Army, and simply as the Afghan Army, is the land force branch of the Afghan Armed Forces. The roots of an army in Afghanistan can be traced back to the early 18th century when the Hotak dynasty was established in Kandahar followed by Ahmad Shah Durrani's rise to power. It was reorganized in 1880 during Emir Abdur Rahman Khan's reign. Afghanistan remained neutral during the First and Second World Wars. From the 1960s to the early 1990s, the Afghan Army was equipped by the Soviet Union.

After the resignation of President Mohammad Najibullah in 1992, the army effectively dissolved. In 1996 the Islamic Emirate of Afghanistan (Taliban regime) took power, creating their own army, which lasted until the United States invasion of Afghanistan in October–November 2001.