He can surely be excused because...drum roll, please...he's a Democrat. They can't be expected to be perfectly clear after saying they would like to be perfectly clear on a topic.
This is one of those guys that should be brought to a VFW meeting in fly-over country for an evening's entertainment. He should be a guest at a River Rat/NamPOW reunion for a 2:00 AM appearance at the hospitality suite. He should visit a Marine barracks for an orientation. We might all like to talk to him about his experiences "when he served in Vietnam":
Five Deferments and a Reserve Slot Stateside
Mr. Blumenthal, that is quite simply called lying. It is claiming an experience which you do not have the right to claim. That demonstrates your unsuitability for public service at the very least.