Did the One Ring "choose" Sméagol over Déagol while they fought over it? Did it intentionally seduce Sméagol perhaps because he was less innocent than Déagol?
I think it seduced both... but the One Ring also needs a strong bearer, so it "made them fight" to see which one should be better suited to bring it.
After all, should it have seduced only Sméagol, probably Déagol wouldn't have entered a deadly fight.
(EDIT: I called the ring "he" instead of "it" in the first time...)