Sentence:  If you can <WSD>retro-engineer</WSD> Sauron's ring, it isn't as magical anymore. It's a matter of the characters getting control of the material, as opposed to being in a situation or universe where this is not really possible. 
Meaning of the word marked with <WSD> tags:  To reverse-engineer; to analyze (an existing item) in order to determine how to replicate it.