In requesting that Obama assert executive privilege, Holder said he is “very concerned that the compelled production to Congress of internal Executive Branch documents generated in the course of the deliberative process concerning its response to congressional oversight would have significant and damaging consequences.” This, he added, “would raise substantial separation of powers concerns and potentially create an imbalance in the relationship” between Congress and the White House.”Let's translate folks.
"Would have significant and damaging consequences" means "If the truth comes out, Obama loses and I go to jail".
"Create an imbalance in the relationship between Congress and the White House.” means that Obama won't be able to just do what he wants, irrespective of what the Constitution says.
Obama and Holder have upped the stakes. Unfortunately for them, they hold the losing hand. That is, as long as Issa and Boehner don't fold. Issa won't, but I'm only 50-50 on Boehner.