What is meant by "The surge is working" and "Win the war in Iraq"?

The surge is working to do what? If we win the war in Iraq what does that mean is different than before the war?  What is our success metric in Irag? 

Measuring the number of Americans killed? Before we started the war there were NO Americans killed there.  So is that success? 

I hear 'stable local governments' is a measure of success.  Are they 'stable'if they follow Sharia law? Is that OK?  If they have no elections bu there is no sectarian violence is that OK?  Since they did not declare war on us - what constitutes "winning the war"?

While I don't believe we can just walk away, I am troubled by what metric will demonstrate acceptable improvement - improvement that will remain after we've gone.