When I had to have a TS/SCI with a SAP for a specific mission in the military, they weren't going to wait for the investigation, poly, etc. so a general just waved his hand and signed a hand written note (to be formally typed up later... which never happened) and, ta-da, I had clearance.

It's just like security in any system... sometimes it needs adjusted for expediency. The key is to be eventually consistent at the very least.