Throughout the 20th century, rebel forces challenged empires, reshaped nations, and inspired both hope and fear. These armed movements, often called guerrillas, emerged from the jungles of Latin America to the deserts of Africa, and they have shaped our concepts of justice, freedom, and power. Yet, despite the prominence of such rebel movements in our history, we know little about how these rebel groups take power, why they win or lose, and what effect their victories have on the structures of government that they impose.

The surprise offensive by rebel factions in Syria has shocked the world. In less than a week, these Islamist militants have pushed into Aleppo and other towns in northern Syria, advancing on a major military road and pounding the regime’s forces. The rebels are part of a loose coalition of groups called the Military Operations Command, led by Abu Mohammed al-Jolani of Hayat Tahrir Al-Sham (HTS), the former branch of al Qaeda in Syria. HTS is backed by Turkey, which has been instrumental in coordinating this offensive.

These rebels are taking a bold step forward, one that could potentially derail peace talks and rekindle the war. Their success suggests that a number of factors, including the presence of well-armed non-state actors, have come together to make it possible for rebel forces to challenge regimes in ways that have been historically impossible. Yet it remains unclear whether this strategy can lead to a stable, functioning state that delivers services and goods to its citizens.