[Taimar]

An interesting notion, Mithadan. If the Nirnaeth had instead been a glorious victory, I don`t think that it necessarily have won the war for the Eldar and Edain. Morgoth would simply have shut Angband tight and sat it out. I doubt that the victorious army would have had the strength necessary to launch a successful assault upon Angband itself. Consider the practical difficulties in besieging the place. It states in the Sil. that their armies lacked the numbers to surround Angband, so Morgoth would have able to send out sorties at will, gradually weakening the besiegers. The lands around Angland were desolate and it would have been difficult to keep a large army supplied. I think that the Eldar and Edain would have retreated and tried to keep Morgoth`s forces hemmed in as best they could. They would certainly have regained lands lost during the Dagor Bragollach, and perhaps have been in a situation akin to that which existed after the Dagor Aglareb, where Morgoth was held in check for a couple of centuries.

However, looking further ahead, there are some more things to think about. The Nirnaeth Arnoediad probably convinced even the proudest of the Noldor and Edain that they could never defeat Morgoth without aid from Valinor. Morgoth was convinced that this help would never arrive, so it led to him becoming overconfident.

Would Tuor ever have arrived in Gondolin? Highly unlikely. I think that the aftermath of the Nirnaeth Arnoediad was what JRR would have termed `eucatastrophe`, since the crushing defeat led ultimately to the marriage of Tuor and Idril, the birth of Earendil and ultimately the salvation of the peoples of Middle-earth.