President Biden made the withdrawal of U.S. troops from Afghanistan a central piece of his foreign policy platform, enacting a plan set in motion by former president Donald Trump, who infamously negotiated with the Taliban for a hasty retreat.

Yet many analysts were caught unprepared for the swiftness of the Taliban advance and the abruptness of the collapse of the U.S.-backed Afghan government on Sunday. But they shouldn’t be. By leaving behind a system of endemic corruption, a government and military overly reliant on foreign support and empowered regional warlords, the United States fomented the very conditions that allowed the brutal Taliban to sweep back into power after 20 years.

Afghanistan was born during the height of British colonialism in Asia in the early 19th century. Seen as a crucial gateway to India, the small landlocked country became a battleground for an imperial contest between the Russian Empire and the British.

The British invaded in 1839 and 1878, and each time Afghans repelled them. However, the British managed to entrench an economic crisis that would endure long after their exit as a colonial power. Despite resisting the British during numerous invasions, by 1879 Afghanistan agreed to a treaty that ended the armed conflict but also saw Great Britain as the de facto manager of Afghanistan’s foreign affairs. In return the colonial power provided Afghanistan with a hefty subsidy.

By restricting Afghanistan’s international connection to only British India and fostering a relationship in which emirs and local rulers were reliant on foreign subsidies to fund their armies and palaces, the nascent nation-state was effectively molded to be dependent on a flow of cash from the outside. Under King Amanullah Khan, Afghanistan invaded British India and fought Britain to an armistice, forcing the colonial power to formally recognize Afghanistan as an independent state in the Treaty of Rawalpindi in 1919. This also ended the British subsidy to the country.

Though now formally independent, Afghanistan’s economic situation had been shaped by British influence for decades. Britain relied heavily on buying off regional leaders to extend its influence, making the country almost entirely reliant on foreign aid. By flooding Afghanistan with payoffs, bribes and aid, the British created a system of endemic corruption in which local chieftains and favorable bureaucrats would enrich themselves while the rest of the country remained relatively poor.