Imagine Sauron without the weakness of the Ring. Not fun.
The only way I could see it happening would be if Galadriel had succumbed to temptation and accepted the One Ring from Frodo. With both the Master Ring and Nenya, Galadriel might have been strong enough to take on Sauron himself; she at least thought so. Alternately, Sauron would have manipulated her just as he had Saruman; letting her think that she was in control until she actually tried to challenge him.
She had an Elven Ring, she'd probably be more of an ally than Saruman.
ze was toch met Nenya en de Ene ring sterker dan Sauron. En ze zou op het begin steun hebben van gondor en de andere volken. En zij zou de ringgeesten er op uit kunnen sturen voor de andere elvenringen en zo onverslaanbaar kunnen worden.