Question for John McCain, Lindsay Graham, Joe Lieberman, etc.

So, if the "surge" was so damned successful, then why did it all come apart as soon as we took our finger out of the dike (tantamount to a cured patient leaving the hospital and dropping dead before he reaches his auto)? I  mean, to me, "works" means that we fixed the thing structurally and that it wasn't any longer the fact that our occupation and check-points were the critical component....You obviously disagree, I guess.