What union general was considered to be insane because he predicted that heavy casualties would be necessary?

Union General George B. McClellan was often criticized and regarded as overly cautious, particularly for his belief that significant casualties were inevitable in battle. His predictions of heavy losses during the Civil War led some to view him as indecisive or even insane, as he frequently hesitated to engage the enemy aggressively. This cautious approach ultimately contributed to his removal from command by President Lincoln.