Why was the surrender of Charles town the worst americandefeat of the war?

The surrender of Charleston in May 1780 was the worst American defeat of the Revolutionary War due to the significant loss of troops and resources, with nearly 5,000 American soldiers captured. This defeat severely weakened the Southern Continental Army and bolstered British control in the South. It also demoralized American forces and shifted the momentum of the war in favor of the British, making it a critical turning point in the conflict.