It only makes sense. Al Gore ran a dreadful campaign in 2000, turning what should have been an easy victory into the boondoggle we all remember. Kerry is apparently trying to outdo him by running an even worse campaign, and if that's his goal, he's doing a smashing job so far.
"Senator Kerry, what about education?"
"I was in Vietnam, dammit. VIETNAM~!"
"Senator, what about the War on Terror?"
"I spent four months in VIETNAM~!"
"Senator, what about the economy?"
"I won three Purple Hearts in VIETNAM~!"
"Senator, what about health care?"
"I will now yield the floor to my fucking psycho wife..."
"... who did not serve, as I did, in VIETNAM~!"