With the benefit of hindsight being 20/20 I think it's the smart move was to forge
the ring in retrospect.
My logic goes thus: It's a given he would have lost the battle at the last alliance regardless. The ring continues while he essentially turned to vapor. That rings very existence sustained him in his 'whispy' years. If he hadn't forged that ring - who's to say he would have been able to return to any semblance of power at all in the 3rd age or ever? Purely my opinion - I have nothing specific to back that up.
To summarize, my opinion is making the ring may be akin to 'not putting all your eggs into a single basket' as well as the 'whole is greater than the sum of the parts'.
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No ring - what would he have hoped to accomplish - play tricky games of deceit w/ the
elves ad nauseum?
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Oh and don't forget, while it didn't work w/ the elves and did little w/ the
dwarves - it gave him notably political sway over 9 leaders of
men 1 of whom crushed the northern half of the remaining former
Numenorean kingdoms,
Arnor. Sure the ring ticked off the elves but he had to show his hand sooner or later anyway and after the last alliance - what threat were they anyway?
I think the real mistake was in the logic of dominating the 3 or the 7 and the mismanagement of the 9. Those 9 could have been continually used to always maintain tight grip on 9 disparate kingdoms of man (including
Gondor itself perhaps - something he sorta made up for w/ the
Palantir). But ultimately they became trinkets to hold over 9 fallible errand boys.
OK I 've rambled enough!
-cya
-T