Unnumbered Tears - what if?

[Maédhros]

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.

I think that you're probable right, but the host of Morgoth would have been greatly reduced, since he had emptied Angband. Perhaps the elves would have ventured inside Angband and could have maybe "Captured" Morgoth.
I wonder if they would capture Morgoth, then what?

[HerenIstarion]

I believe that in the case (as well as elswhere, and even if unconsiously so), Tolkien was employing the Christian idea of humiliation as the means of reducing pride and making one capable of receivibng heaven's gifts. To put it short - without utterly shattered hope, the Eldar would not have been ready to accept help from the West (the point being, we are so good at beating Morgoth, who cares what that Mandos told us back than, ha!). The loss helped tham see that there were no other resources to rely upon but the West for them, while the victory would simply postpone the defeat

[Finwe]

I think that the Valar wanted the Noldor to humble themselves before them, before thinking of giving them aid. When Earendil set out on his voyage West, it wasn't his action itself that impressed the Valar, it was the humility behind it. Without that humility (which wouldn't have been there if the Elves had won the Nirnaeth Arnoediad), the Valar wouldn't have sent aid.

On a second note, perhaps this victory would have just put off that final flood of darkness. If this victory could have been comparable to, say, the Dagor Aglareb, then the Elves would eventually have been defeated by Morgoth anyway. This would just put off the War of Wrath.

[Nilpaurion Felagund]

I think Morgoth's embryonic force of winged dragons must have existed by that time. Had the Eldar and Edain won Nirnaeth, and threatened his stronghold, surely he would have released them. Considering the dismay of the Hosts of Valinor when they were released, their effect on the far smaller army of the Eldar would have been ruinous.

But enough about that.

...the Eldar might have won the day, had all their host proved faithful.

(The Silmarillion 20 - emphasis mine)

Mandos' prophecy at work. So the sentence could have meant:

The Eldar might have won the day, were they not under the doom of Mandos.

Since the doom of Mandos had taken effect when they rebelled, and left for Middle-earth, the only way they could not be under Mandos' curse was if they never rebelled and left Valinor. That means they would have won the fifth battle were they not there.

Crazy, I know. It just means victory at Nirnaeth was impossible.

You could have said that earlier.

I was trying to support my statement! Statements need supporting facts, or they'll be like legless Ents, or legless Balrogs.

[Nilpaurion Felagund]

[Mandos(?): ]To evil end shall all things turn that [the House of Fëanor] begin well; and by treason of kin unto kin, and fear of treason, shall this come to pass.

(The Silmarillion 9)

...and [Maedhros, son of Fëanor] began those counsels [i.e., unite again, and make new league and common council] for the raising of the fortunes of the Eldar that are called the Union of Maedhros.

(The Silmarillion 20)

See? The battle was doomed from the beginning.

[Luthien_ Tinuviel]

And taking that one step further, they had to lose by logic, too. Since "to evil end shall all things turn that [the House of Fëanor] begin well....", they must ultimately have been defeated. Seeing as they won the second and third battles, it stands to reason that they must then lose the fourth and fifth battles, as they did. It seems to me that if they had paid the Doom of Mandos any heed at all, they should have expected this. But whether or not they had seen it coming, chances are they would have been defeated anyway. Would they have been routed as thoroughly as they were, though, is the question. I think they would have; doom in effect an' all that, but perhaps not. Yet going into the Ninaeth Arnoediad expecting a loss would have severely decreased morale and even further lowered the chances of victory so...... they were doomed, as Elenrod said. Every way you look at it, they were doomed.

[Finwe]

Poor Noldor.

Also, the line "they might have won had all their hosts proved faithful" doesn't concretely say that they would have won. It just says that they might have won. Even if the Easterling men had proved faithful, Morgoth was still infinitely more resourceful and powerful than the forces of the Elves. There were plenty of ways he could still defeat them.