In Margaret Atwood's "The Year of the Flood," the quote "A wall that cannot be defended is no sooner built than ended" emphasizes the futility of creating barriers that lack the means of protection. It suggests that any attempt to isolate oneself or create security is pointless if those walls can be easily breached or are poorly constructed. Such walls symbolize not just physical boundaries, but also emotional and societal divisions that ultimately prove ineffective.

This sentiment reflects deeper themes in Atwood's work, which often explores the fragility of human constructs. The narrative warns against the illusion of safety provided by superficial barriers, inviting readers to consider the importance of resilience and true defense mechanisms. In a world where real threats exist, simplistic solutions fail to provide lasting security, highlighting the need for vigilance and strength in the face of challenges.