what exactly did Rumsfeld 'bungle'?
"what exactly did Rumsfeld 'bungle'?"
In his own words, "Go minimalist!"
But he kept the Star Wars Part Deux money safe.
/sarc
Not accepting the surrender of Iraqi forces from Iraqi generals when offered and letting them melt away instead. Dissolving the Iraqi Army. Deferring to the Iraqi government when they protested our actions. Not treating Muqtada al-Sadr like he did Uday and Qusay. Not finishing the job during First Fallujah. Letting the Iraqis write their own constitution accepting Sharia law.
In other words, not being aggressive enough.
His decision to use a small force, as opposed to a larger one. It worked out fine for the actual invasion, but not for the occupation/pacification. And the small army approach was more a concession to reality than to a philosophical approach.
"what exactly did Rumsfeld 'bungle'?"
Isn't it obvious? He didn't agree with McPain.