I think Dems' problem with understanding national security is two-fold.
First off, their opinion makers came of age during the Vietnam draft era. Their "glory days" when they were 18 years old, still had their hair, were spent angrily opposing a war.
It forged their view of the world.
They now, are stuck. They cannot understand that Iraq is not Vietnam. Because Vietnam is all they have ever understood.
The other part of their problem, is Richard Nixon.
Nixon, in retrospect - would have done well to act like Clinton.
He didn't. Believing resignation was honorable - he exhibited the weakness, with which the left destroyed him.
There's a lesson there.
A point to remember is that the rhetoric of the Democratic Party has been HIJACKED by the Communist/Socialist/Maoist Anti-War crowd, with MASSIVE financing from Soros,et.al .....
Without the massive CASH thrown around by Soros through MoveOn, the World Workers Party organ TruthOut, and others, Liberals wouldn't even be allowed at a reasonable discussion.
As MoveOn said in 2004, they have "Bought And Paid For" the Democratic Party, while sane and sensible Democrats are left standing outside in the rain, wondering what happened...
The "Machine" is trying to fight back, and retake control, through things like moving the 1st primary to a Machine-Controlled State, but it's already too late for them....