John Piper has explicitly addressed the question I raised:

When we teach that our right standing with God is attained through the imputation of Christ’s obedience to our account (Romans 5:19; 2 Corinthians 5:21; Romans 4:6, 11; 10:3), does this imply that the work of Christ on the cross—his final suffering and death—is insufficient for our justification?

That is awesome!

But this is his answer:

Is the death of Jesus sufficient to cleanse us from all our sins? Yes, but only as the climax of a sinless life…

So the death of the Son of God is sufficient to cover all our sins as the climax of a sinless life. This is no disparagement to the cross. It is not adding to the cross. The New Testament writers saw the death of Christ as the climax of his life. His whole life was designed to bring him to the cross (Mark 10:45; John 12:27; Hebrews 2:14). That is why he was born, and why he lived. To speak of the saving effect of his death was therefore to speak of his death as the sum and climax of his sinless life…. (read the entire piece).

But who ever denied that?  I don’t think that was ever what the debate was about.  I don’t see how it realy accounts for Dr. Piper’s own language.

I don’t think this would be that big an issue except we are all hearing about some huge Wright refutation that Piper is about to come out with.  Is this really the kind of thing–so confusingly expressed–that is worth going to war over with another Christian teacher?  Piper has written some wonderful books.  Desiring God, The Pleasures of God, and Future Grace all have had great impact on my life.  But it looks to me like he has been changing direction in a way that doesn’t seem to utilize the clarity I have admired in these works.  I wish he would write another big book on his own thinking rather than spending his time publishing shorter tracts and refutations.