Now, I am not an authority of Kerry's complete time in the military, but I believe he spent quite a bit of time on a Navy ship before hitting Vietnam.  Still, time alone in a combat zone is not an accurate way to put one's service into context.  It's what one does and encounters in that time period.

For example, would it be fair to judge a General's time in a combat zone to that of an infantryman?  Of course not, because we can probably safely assume that the General's ass is safely in the rear in a safe location. 

From what it appears, Kerry was a very aggressive soldier for those four months and in an environment of what seems to be of steady combat.  Psychological studies have shown that 60 days of combat is enough to cause post-tramautic stress syndrome. 

My point is, in my profession we have saying that goes something like, "Some adminstrators have twenty years of one year of experience."  In other words, they barely worked one year on the street and have relived it for 19 more years.  Now some might say Kerry is doing the same thing, however, if he was the sort to have been aggressive and assertive and always pushing it to the limit, then that is different to me than a pure pencil pusher who is just trying to get by to make it to that adminstrative ladder. 

PS.....here is info on one of the author's of the book tearing apart Kerry's war background...he seems like quite the unbiased (sarcasm) person....

http://mediamatters.org/items/200408060010