Why didn't 👁️Sauron use Numenor to conquer Middle Earth for him?

[BalrogRingDestroyer]

While it might have been nice to get Numenor out of the way, his scheme to trick the Numenoreans into attacking Valinor led to the sinking of Numenor, which was a great defeat for him, as his form got destroyed (maybe he could have survived the destruction of the One Ring (albeit as a weak Mair) if his body hadn't been destroyed when Numenor sunk.


Also, it seems that the Numenoreans were already power hungry and taking over parts of Middle Earth. As part of his Melkor cult, he could have easily gotten them to attack Middle Earth to get more victims to sacrifice, until the dwarves , Hobbits, and other men had been subdued. At this point, he would ask to be freed so that they could take on the Elves. As the Numenoreans had come to loathe the Elves, they may well have agreed, and marched with him to take down the Elves.

Once the Elves had fallen, Sauron could essentially use the Numenorean kings as puppet rulers to rule all of Middle Earth.

Indeed, in time, he could corrupt all the races (though I suspect some elves, men, dwarves, and hobbits would go into hiding and still be loyal to the Valar.)

In time, with the people of Middle Earth corrupted, something even Melkor hadn't quite achieved (he got men and messed some with the Elves but never went this far), Sauron could:

1) Try and free Melkor from the Door of Night
2.) With or without Melkor, take his Grand Armada of Middle Earth and personally attack Valinor with it Here, if Eru wanted to stop Sauron, he'd have to destroy most of the population of Middle Earth.

 

[Alcuin]

Sauron didn’t need the Númenóreans to conquer Middle-earth. But for the Númenóreans, he’d have already taken control of Middle-earth: they first checked his assault on Lindon around Second Age 1700, ending the War of the Elves and Sauron with a smashing defeat for Mordor (Sauron himself barely escaped!), then followed on by challenging his control of Middle-earth by building a massive military base at Umbar, within striking distance of Mordor, followed by more military installations along the western coast of Middle-earth. (Pelargir, the future core of Gondor, was one of these.)

Númenor itself, however, was outside Sauron’s grasp. Even if he’d been able to raise his own navy, he probably faced defeat at sea had he tried to invade. Ar-Pharazôn’s arrogance and ignorant presumption – he assumed he could through his own efforts cow and overcome a Maia, a creature whose native intelligence and power far outstripped his own, Númenórean though he was – were an opportunity for Sauron to overthrow the descendants of his old enemies, the Edain of Beleriand, thereby taking revenge upon them. (I wrote a tongue-in-cheek essay on this many years ago.)

Sauron’s plan was fiendish: He convinced the Númenóreans to attack the Elves and Ainur in Valinor itself. The Valar and Maiar were forbidden to kill the Children of Eru. By sending the King of Númenor and his followers against the Valar in physical combat, he set up an irresolvable moral and ethic conundrum for the Valar. Their only response was to turn the problem over to Eru, who destroyed both the Númenórean invaders of Valinor and Númenor itself, whose people had given themselves over to wickedness and folly, sparing only those few of the Faithful fortunate enough to be aboard one of the nine ships of Elendil and his sons.

 

[Claro Del Rosario]

Sauron can conquer Middle Earth but the Numenorians stand on his way. He was on the verge of doing it during the War of the rings between Sauron and the elves of Eregion, Lindon and Rivendell when the Numenorians arrived and tip the balance in favor of the elves.
After this terrible defeat Sauron vowed to destroy first the Numenorians by deceving them that the only way to avoid death which the Numenorian King feared greatly is to invade Aman. Sauron knows that to do so is suicide on the part of the Numenorians who were forbidden by the Valar with consent from Eru not to sail to the West. Once the Numenorians are destroyed Sauron's next plan is to dominate the whole of Middle Earth with his armies of orcs, throlls. fell beast and the Nazguls.

But Sauron did not anticipate that Eru will change the geography of the earth permanently: sinking Numenor and then making the earth round and removing Aman from the face of the earth. He drown in the sinking and lost his ability to shiftshape and thus his ability to appear in fair form to deceive elves, men, hobbits and dwarves. After returning to middle earth (in Mordor) Sauron immediately wage war against the free people (with Gondor first). He was opposed by the Last Alliance between Men and Elves under Gil-Galad, Cerdan, Elrond, Elendil, Isildur and Anarion. In the last battle Sauron was killed and the ring taken from him but at the cost of the lives of Gil-Galad, Elendil and Anarion.

But going back to the question. Sauron could not have motivated nor convinced the Numenorians to conquer Middle Earth since Sauron is just an adviser to the very proud king Ar-Pharazon who would find no benefit in conquering Middle Earth. The Numenorian King already dominates the affairs of men in Middle Earth and because of this he believes that he is indeed the "King of Men". Conquering them by force would not alter this fact nor improve upon it since he would find no value in waging war against the people who are already subjected to his dominion. Most importantly conquering Middle Earth would not solve his problem about his mortality and assuage his fear of death.

Sauron did not control the mind of the King but rather play with his fear - fear of death and deceived him into believing that invading Aman and living there will make him an immortal. Sauron could not command the proud Numenorian King as if he himself is the King of Numenor. Always remember that the King went to Middle Earth with a big army to challenge Sauron whose supporters fled for fear of the giant Numenorians. Sauron himself trembled in fear at the sight of the terrible looking Numenorians, big, tall as giants with the intent to destroy him and swallowed his pride to be taken as a prisoner to Numenor.