[Formendacil]

Perhaps it's a fault of my aging memory... and the lack of a Silmarillion copy close at hand, but does anyone here recall if it is said that the treachery of Ulfang began BEFORE or AFTER Maedhros retook the Gap (sidenote... the Gap of Rohan is clearly not the only franchise of the chain in Middle-Earth).

If Ulfang and the others went over to Morgoth AFTER Maedhros retook the Gap, ie. after Morgoth was alerted to what Maedhros is up to, then it is possible to assume that he did NOT, in fact, know Maedhros' plans, in which case Macalaure is probably correct in stating that retaking the Gap was probably a fatal error.

On the other hand, if Ulfang and his crew had already betrayed Maedhros, then we're left with the "well Ulfang could have told him anyway".