Bilbo´s treachery

[Inziladun]

Originally Posted by Leaf

Coming back to the case of Smeagol and Deagol, it seems to me that there are two possibilities:

1. The Ring's power was, at the time of the incident, stronger than it was ever again afterwards.

That was not the case. The Ring grew in power along with its maker, for one thing. It was more powerful after Sauron returned to Mordor and openly declared his return, and it continued to increase in potency as Sauron's strength rose.

Originally Posted by Leaf

2. Smeagol's character is distinguishable and profoundly different from that of the whole lot of other people who knew about the Ring and were around to take it.

I think this is the key. Sméagol was a mean, sneaking sort from his birth. He had a head for mischief and secrecy
It was said of the Nazgûl that they had been conquered by their rings sooner or later, depending on their native willpower and character. The same would be true to a greater extent with the One.
Sméagol didn't resist the Ring because he lacked the desire to do so. It called to his lowest, deadliest wants, and he responded. Even had he possessed the awareness of Frodo and Sam of the Ring's potential, I doubt he could have been swayed from using the Ring.