After the Battle of the Pelennor Fields, Aragorn freed the Dead Men of Dunharrow. However, he could have used them in the Battle of the Black Gate too. Was the mission of the undead only to “defend”?
The army of the dead could easily have passed the Gate and drawn the attention of orcs, goblins, and trolls so that Frodo and Sam could just carry the ring without disguising themselves under restraining and exhausting armor. If they had done that, they would not have been so tired and they could have just thrown the ring down into the lava of Mount Doom. Gollum would have survived and the third giant eagle could have carried him away too.
This raises another question: Did Mithrandír bring three eagles because he was thinking that Gollum might survive? One eagle for Frodo, one for Sam, and one for old Sméagol? Or was it just for protection against Nazgûl attacks? Didn’t the Nazgûl die after Mount Doom erupted? (I know that’s a third question but at least it’s on a related topic.)
The way is shut.
It was made by those who are Dead.
And the Dead keep it.
The way is shut.