Umm, no, he hasn't earned the right to say anything he wants. Not when he slanders currently serving marines!
As for his impressive background, GET SERIOUS! You want impressive? Look at the current JCS Chief, Pete Pace! Look at Norm Schwartzkopf! Look at Colin Powell! Too many to name who have truly impressive backgrounds! If Murtha impresses you, I'd like to know your impression of Jf'nKerry!
The men you mentioned obviously have very impressive records. That doesn't detract from those with "less" impressive records. I haven't heard what he said, other than his opinion on the current Marines charged with murder. I haven't kept up with it much, so you all may be right...