It can be done. We've seen Vermeil, Gibbs, Parcells & Shanahan all come out of retirement and have a few years of success on teams that were struggling. They come in, shake things up a little, turn it around and hand it off to another coach that should hopefully be able to retain their success to a certain degree whether a bit higher or a bit lower. But it's been done before. And Coughlin is certainly capable of producing the same exact results. 

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