Why can a conventional army lose a guerrilla war even when it has more weapons and soldiers?

A conventional army may lose a guerrilla war despite possessing superior weapons and troop numbers because guerrilla warfare is a form of asymmetrical warfare where victory is defined differently for each side. As noted by Henry Kissinger, the guerrilla wins if they do not lose, whereas the conventional army loses if it does not win.1

Key reasons for this disparity include:

• Erosion of Will: The primary goal of the guerrilla is to exhaust the enemy's political and social will to sustain the costs of the war. Conventional powers often withdraw not due to military defeat, but because they lack the resolve to continue the conflict.1
• Tactical Limitations: Guerrilla fighters avoid open battle, instead using ambush, sabotage, and harassment. Because they lack fixed bases, conventional armies cannot effectively use their technological advantages, such as aerial bombardment, without risking high civilian casualties and further alienating the local population.12
• Popular Support: Guerrillas rely on the local population for supplies, intelligence, and sanctuary. When conventional armies use brutal tactics or indiscriminate force, they often alienate the populace, driving them to support the insurgency.2314
• Political Nature: Insurgencies are often rooted in legitimate socioeconomic or political grievances. If a government relies solely on military force rather than addressing these underlying issues, it often fails to achieve a lasting resolution.24