In December 1979, the Soviet Union launched a major offensive inside Afghanistan. What was, on paper, a one-sided military conflict would rage on for ten years, becoming for the Russians what Vietnam had been to the Americans. The Soviet army fought to maintain communist control of Afghanistan, suppress dissent and improve the Soviet Union's geopolitical standing. For the West, the war for Afghanistan was seen as that of a minor power resisting a superpower aggressor – and an opportunity.

It would soon become much more than a fight for one country, with the mountains of Afghanistan becoming the battleground for a significant Cold War proxy conflict. Propped up by American (and in particular CIA) support, the religious warriors of the Afghan Mujahedin took the fight to the Soviet forces. Armed with an internationally supplied armoury of the most basic but also, eventually, sophisticated weaponry, as well as other forms of equipment, medical supplies and military training, the Mujahedin were able to hold the Soviets at bay for a decade. For the United States, this was an opportunity to embarrass and weaken the Soviet Union and its communist cause; yet no significant attention was paid to what a generation of fighters, emboldened and trained, might do once the conflict was over.

The Soviet intervention in December 1979 came at a critical juncture in the evolution of the Cold War. Just as the era of détente was coming to an end, attention was temporarily diverted elsewhere. The news of the Ayatollah Khomeini's Islamic Republic in Iran (see Chapter 12) had been greeted enthusiastically in Moscow, with the Soviet leadership encouraging its anti-Western sentiments. Despite the fact that the Tudeh Party, Iran’s communist movement, was its most natural ally, for the Soviet Union the maxim of ‘my enemy's enemy is my friend’ was a powerful one. Yet it would be support for another communist party that would trigger the intervention in Afghanistan.

The People's Democratic Party of Afghanistan had been created in 1965 with the support and encouragement of Moscow. It quickly splintered into warring offshoots, with the Khalq faction eventually consolidating power in April 1978. On 30 April the new communist government formed the Democratic Republic of Afghanistan, which was recognised a few hours later by the Soviet Union.