In Timpte, we emphasized that the employee's conduct was not impulsive but constituted a deliberate refusal to stop using filthy language in union campaign material after being requested to do so.
In Maryland Drydock Co. v. NLRB, 183 F.2d 538, 539 (4th Cir. 1950), we held that an employer was entitled to maintain discipline by prohibiting "defamatory and insulting statements which reasonably tend to destroy such discipline....