[Iarhen]

I recognise the fact that Melian was a powerful Maia (I dont think, though, that she was the "most powerful" one, because Sauron is held to be the most powerful one) and just because of it, she has an advantage in terms of ratial powers.

But remember that it is also told that some of the Eldar that lived in Valinor, at least the greatest among the Eldar (Galadriel included) grew to be as powerful as a maia. Maybe not as powerful as Melian, but close.

So, with the aid of Nenya, and the teachings in Valinor, and summing up the training of Galadriel by Melian, maybe the power of Galadriel was close to Melian's.

But about the important thing. I know Nenya was not designed as a Ring for battle. But its powers was to protect a land from all kind of decay. If the ring was able to stop the effects of time, I presume that it gave Galadriel the power to affect the enemies that would try to enter and attack Lorien.

In what way? Even though some orcs and Gollum were able to enter the Golden Wood, the main force that kept Sauron, Barad Dur and Dol Guldur out of Lorien was Galadriel. Remember that when the 3 assaults occurred against Laurelindorenan, the main power that kept the Evil Forces out of Lorien was Galadriel. Tolkien even states that only Sauron, physically present in the borders of the Wood with the power of his Ruling Ring, would be able to enter and break the defenses of the Wood. Meaning that not from a distance, and certainly not without his ring, Sauron could not enter Lorien. Much less conquer it.

So, even Sauron, the most powerful maia, would have a terrible time dealing with Galadriel. My guess is that, even though Melian was more powerful than Galadriel (but not that much), Galadriel's defenses kept Lorien a safe place. And that was when Sauron was at the height of his power (not only personal, but in terms of armies, allies, advantages, etc.).

P.S. But then, maybe Nenya was not the main reason that Lorien was a safe place. Then, it was Galadriel. Don`t you think?