If Denethor hadn't committed suicide

[Formendacil]

Originally Posted by Kitanna

If Denethor had survived, without Sauron to show ruin in the palantir anymore could it have been possible for him to recover and embrace Aragorn as his king?

To me this seems a highly unlikely scenario. Denethor's antipathy towards Aragorn--"the last of a ragged house, long bereft of lordship and dignity"--goes deeper than just the poisoning of his mind by the Palantír. Indeed, it seems far more the case to me that while Denethor was somewhat solidified in this position by the use of the Palantír, which gave him a sense of doom and of being the only hope of the West--where was that useless Arnorian lordling, anyway, when needed?--his dislike of Aragorn goes deeper. The Appendices certainly suggest that Denethor had no love for Aragorn:

Originally Posted by Appendix A, I, iv

'There was dismay in the City at the departure of Thorongil, and to all men it seemed a great loss, unless it were to Denethor, son of Ecthelion, a man now ripe for the Stewardship, to which after four years he succeeded on the death of his father.

Clearly, Denethor saw his own position endangered by Thorongil then, and was "ripe" for ruling--which I would read to mean not only "ready," but, in this context, "eager." However, the passage has more to say:

Originally Posted by Appendix A, I, iv

Denether II was a proud man, tall, valiant, and more kingly than any man that had appeared in Gondor for many lives of men; and he was wise also, and far-sighted, and learned in lore. Indeed he was as like to Thorongil as to one of nearest kin, and yet was ever placed second to the stranger in the hears of men and the esteem of his father.

Ouch! Denethor, then, had personal reasons to dislike Aragorn--imagine being made second in your own father's affections? Let's finish quoting this passage, for the sake of completion.

Originally Posted by Appendix A, I, iv

At the time many though that Thornginl had departed before his rival became his master; though indeed Thorongil had never vied with Denethor, nor held himself higher than the servant of his father. And in one matter only were their counsels to the Steward at variance: Thorongil often warned Ecthelion not to put trust in Saruman the White in Isengard, but to welcome rather Gandalf the Grey. But the was little love between Denethor and Gandalf; and after the days of Ecthelion there was less welcome for the Grey Pilgrim in Minas Tirith. Therefore later, when all was made clear, many believed that Denethor, who was subtle in mind and looked further and deeper than other men of his day, had discovered who this stranger Thorongil in truth was, and suspected that he and Mithrandir designed to supplant him.

Personally, I take this passage to read that Denethor had figured out Aragorn's identity before he ever used the Palantír. And, really, how would the Palantír have confirmed this? It might have shown that Aragorn was a friend of Elves, a Ranger of the North, and high in their ranks... but the confirmation that he was the Heir of Isildur does not seem to me the sort of thing that the Palantír would have been a great help with.

Consequently, had Denethor survived the Siege of Gondor, I do not think he would ever have welcome Aragorn. Rather, it would only seem to him that Aragorn had, indeed, conspired with Gandalf to supplant him, and that the War of the Ring had been the seized upon pretext. Denethor's position is crystalline-clear: "I am the Steward of the House of Anárion. I will not step down to be the dotard chamberlain of an upstart. Even were his claim proved to me, still he comes but from the line of Isildur."

Admittedly, these words are spoken in the fury of his last minutes, but they represent Denethor's convinced opinions on the issue, both personally and legally. Personally, he will not submit to Aragorn, defeated by his old rival in his old age. Additionally, he has convinced himself that Pelendur's precedent must still reject the Heir of Arvedui.

To me, it does seem likely that Denethor would not have mounted a resistance. In acknowledgement of the healing of Faramir and seeing the support of the people, Denethor may well (if alive) have stepped down... but I do not think (barring a miracle) it is sensible to think he could ever have accepted Aragorn as king. At best, he would have kept his mouth shut for the sake of a united Gondor and let Faramir's opinions guide those of his children, so that there would not be another "kinstrife" between the Heirs of Elessar and the Heirs of Denethor.