The Af-Pak region is a concept and military/political shorthand used primarily by the United States and NATO to refer to Afghanistan and Pakistan jointly. It is not a formal institution or legal provision, but a strategic framing that treats the two sovereign nations as "one theater of war" or "one challenge".
The term gained widespread use in early February 2009, following a speech by US diplomat Richard Holbrooke, the US special envoy to the region, on February 8, 2009. The concept was formally adopted as the cornerstone of the Obama administration's comprehensive new strategy for the region, announced on March 27, 2009. The problem it was created to solve was the presence of the "international terrorist movement" and al-Qaeda safe havens straddling the ill-defined border, the Durand Line.
The strategy worked through a regional approach that included a trilateral framework between Afghanistan, Pakistan, and the United States to enhance intelligence sharing and military cooperation. It also involved significant US and international support for Pakistan, including $1.5 billion a year authorized by the Kerry-Lugar bill over five years, linked to Pakistan's performance against terror. The concept connects to the historical issue of the Pashtun ethnic group, which is split by the Durand Line, and the long-standing Pashtunistan irredentist claims.
The concept has since been largely superseded, with critics calling for the "failed AfPak" approach to be abandoned by October 2020. The US withdrawal from Afghanistan in 2021 fundamentally altered the context of the "one theater of war," shifting the focus away from a unified military strategy.