Uh...Carter served on submarines....they get combat pay whenever they went out to sea (or they used to until the late 1980s).  Futhermore, most of the sea duty of submarines is classified and stays that way for decades.

My father (subs for 26 years0 went to DC about 5 yeras ago to get a medal for events in the Pacfic from the 1960s.

But Johnson was in the Navy for roughly 3 months and made sure he was in a combat zone so he could claim he was a war hero

As for Dukakis, he was in teh army in 1958...we were not at war, is taht his fault?