Potential Use of the Dead Men of Dunharrow.

[Gordis]

Good points, everyone.

Originally Posted by Boromir88

And eventhough the Wiki has shown control over dead spirits, the Dead Men were under Aragorn's power, because of an oath. Oaths in Middle-earth are very powerful things, and I can't imagine the Wiki having the power to override an oath.

The naked spirits of the Dead of Dunharrow were held in ME by their unfulfilled oath, yes, but still I think they followed Aragorn willingly- they followed him because they wanted out, they wanted to get the Gift and to leave. It was their free choice, not that they were compelled to follow him by some magical contract.
They still had their free will, were not some zombies, and as such they could be theoretically led astray by some other influence or by fear. As living Man they had once refused to fight out of fear of Sauron, so it could have happened again. As bodiless spirits they were very vulnerable to necromantic powers of Sauron and the WK. They chose to obey Aragorn, but they might have been compelled by Necromancy to obey Sauron. That's why I agree with JeffF that Aragorn dared not lead them anywhere near Mordor.

Another reason not to bring the Dead to Pelennor would be that (unlike the Nazgul) the Dead were unable to control the fear they emitted. They had been frightening the population on both sides of the Mountins for ages, their fear lay heavily on the Grey company they followed and on the Gondorian allies. Aragornwould have been unable to muster a human force in Southern Gondor if the Dead were still there. He had to choose: the army of Dead or the army of Southern Gondor

To bring the Dead to Pelennor would likely make the Mortal Men on both sides run away screaming. The cavalry (including that of Rohan) would be most vulnerable, unable to control the horses. So, that would be a battle between the Dead on one side and the Nazgul and Orcs instilled with battle-madness by the Nazgul on the other side. And a single well-chosen spell by the WK could send the Dead flying in fear.

And finally think of Aragorn's PR issue. Here comes a total stranger claiming to be the King Returned with an army of the Dead at his heels. Sure his ability to command the Dead would have been a solid proof of his descent from Isildur - but that is for the learned in Lore, not for common people. For ordinary Gondoreans it would only be scary: they would see it as dark sorcery, most likely, and such practices are of the Enemy. Instead of coming as leader of Men, he comes as a necromancer, scattering the allies and foes alike and frightening the population of Minas Tirith out of their wits. Ahem - how is he better than the Witch-King then?