Don't get to war with McClellan. You mistake him if you underrate him. He must begin to move soon and I think he will. If he can threaten Richmond and cause Johnston to fall back from Manassas, he will relieve the Capital, which is the reason why foreign Governments talk of acknowledging the Southern Independence.
SOURCE: Rachel Sherman Thorndike, Editor, The Sherman letters: correspondence between General and Senator Sherman from 1837 to 1891, p. 140