S MANY of you know, I was the original (and most vocal) proponent of the firm’s business-casual policy . . . I am beginning to think that I made a mistake-”

So began the attention-grabbing message from Constance A. Fratianni to employees of Shearman & Sterling around the world, sent Tuesday via e-mail. A copy of the post from Ms. Fratianni, the firm’s personnel partner, was obtained by the New York Law Journal.