Established by Usama Bin Ladin in 1988 with Arabs who fought in Afghanistan against the Soviet Union, al-Qa‘ida’s declared goal is the establishment of a pan-Islamic caliphate throughout the Muslim world. Toward this end, al-Qa‘ida seeks to unite Muslims to fight the West, especially the United States, as a means of overthrowing Muslim regimes al-Qa‘ida deems “apostate,” expelling Western influence from Muslim countries, and defeating Israel. Al-Qa‘ida issued a statement in February 1998 under the banner of “the World Islamic Front for Jihad Against the Jews and Crusaders” saying it was the duty of all Muslims to kill US citizens—civilian and military—and their allies everywhere. The group merged with the Egyptian Islamic Jihad (al-Jihad) in June 2001.

On 11 September 2001, 19 al-Qa‘ida suicide attackers hijacked and crashed four US commercial jets—two into the World Trade Center in New York City, one into the Pentagon near Washington, D.C., and a fourth into a field in Shanksville,Pennsylvania— leaving nearly 3,000 people dead. Al-Qa‘ida also directed the 12 October 2000 attack on the USS Cole in the port of Aden, Yemen, which killed 17 US sailors and injured another 39, and conducted the bombings in August 1998 of the US embassies in Nairobi, Kenya, and Dar es Salaam, Tanzania, killing 224 people and injuring more than 5,000. Since 2002, al-Qa‘ida and affiliated groups have conducted attacks worldwide, including in Europe, North Africa, South Asia, Southeast Asia, and the Middle East.

In 2005, Ayman al-Zawahiri, then Bin Ladin’s deputy and now the leader of al-Qa‘ida, publicly claimed al-Qa‘ida’s involvement
in the 7 July 2005 bus bombings in the United Kingdom. In 2006, British security services foiled an al-Qa‘ida plot to detonate explosives on up to 10 transatlantic flights originating from London’s Heathrow airport. Also in 2006, al-Zawahiri announced that the Algerian Salafist Group for Preaching and Combat had joined al-Qa‘ida, adopting the name al-Qa‘ida in the Lands of the Islamic Maghreb. In 2009, extremist leaders in Yemen and Saudi Arabia reportedly announced they had merged to fight under the banner of al-Qa‘ida in the Arabian Peninsula.

On 2 May 2011, US forces raided a compound in Abbottabad, Pakistan, resulting in the death of Bin Ladin. His death, in addition to significant losses to al-Qa‘ida’s command structure based in the tribal areas of Pakistan since early 2008, has left the group at its weakest since the fall of the Afghan Taliban in late 2001. In the aftermath of Bin Ladin’s death, al-Qa‘ida leaders moved quickly to name al-Zawahiri as his successor. Since this announcement, regional affiliates have publicly sworn allegiance and pledged support to him. Al-Qa‘ida remains a cohesive organization and al-Qa‘ida core’s leadership continues to be important to the global movement.

In June 2012, Abu Yahya al-Libi, widely reported to be al-Qa‘ida’s “general manager,” was killed in Pakistan. Despite this and other leadership losses, al-Qa‘ida remains committed to conducting attacks in the United States and against American interests abroad. The group has advanced a number of unsuccessful plots in the past several years, including against the United States and Europe. This highlights al-Qa‘ida’s ability to continue some attack preparations while under sustained counterterrorism pressure and suggests it may be plotting additional attacks against the United States at home or overseas.