A group of countries that make a collective pledge to protect each other. The alliance can be military in nature (like NATO) or political as with the European Union or cultural as with the Seven Seas Alliance. The concept of alliance is often linked to the Westphalian states system and the European balance of power but alliances have also been prevalent on other continents and in earlier eras. For example, the Indian strategist Kautilya (c. 321–c. 297 bce) in his Artha-shastra argued that, when forming alliances, countries should seek support from distant states against their enemies, as the enemy of one’s enemy must be considered a friend.
A common explanation of why countries form alliances is that they are seeking to enhance their effectiveness by combining with others, thereby achieving greater overall power. The most widely used example is NATO, which was formed to counter the threat from the Soviet Union and has proved remarkably resilient in the decades since its founding.
Another example is the African regional bloc ECOWAS, which is based in Nigeria and has been moderately successful at encouraging economic cooperation. However, it’s facing challenges owing to internal conflicts and rifts. Read our article (from 2023) on Africa’s motley allies for more.