The opinion
ROGERS, Circuit Judge,
dissenting.
This case presents both a close factual issue and a close legal issue. Because on balance I would resolve both issues in favor of the union, I respectfully dissent.
*587 When Ahern put down his co-worker’s name as the sender of a complaint, he may have contemplated that the co-worker would get in trouble. But the ALJ explicitly found that Ahern did not so contemplate, and I would accept that conclusion. JA 10. I recognize that deference regarding fact-finding under the substantial evidence standard is accorded to the Board and not to the ALJ. But where the factual determination of an ALJ is based on a credibility determination, we may more readily conclude that the Board’s determination, if indeed contrary, lacks substantial evidence. See NLRB v. Universal Camera Corp., 190 F.2d 429, 430-31 (2d Cir.1951) (L. Hand, J., on remand); see also Tel Data Corp. v. NLRB, 90 F.3d 1195, 1198 (6th Cir.1996).
Assuming then that Ahern did not intend, but at most created a small possibility, that his coworker would get in trouble, Ahern did not lose the statutory protection afforded his sending an anonymous work-related complaint. The Board of course has primary responsibility for defining what types of actions are sufficient to lose protection of the Act. But such definitional power cannot — in light of the apparent congressional policy — be so broad as to let the Board permit the termination of an employee for otherwise-protected conduct because of such a minor risk.