It's easy to understand John McCain's mind set. To date, only 4,109 U.S. troops have died in the Iraq War.
We lost more guys than that just during the Tet Offensive between January 30th and September 23rd in 1968 in the Vietnam War. Estimated KIAs: 58,209.

The guys in the Korean War had it even worse; they walked, crawled, ate, and slept in freezing rain and waist deep snow. Estimated KIAs: 36,516

Then there was World War II where guys left home expecting to fight until they were killed or the war was over. Estimated KIAs: 417,000