I fail to understand what a Federal Intelligence organization bill has to do with immigration, legal or otherwise.
The bill was supposed to implement the recommendations of the 9/11 commission, among which was the securing of documentation for federal identification. Some states give drivers licenses to illegal aliens, and seven of the 9/11 hijackers obtained licenses through illegal alien loopholes, and boarded planes with them.
Sensenbrenner's provison would have disallowed the use of drivers licenses from the states that issue them to illegals for federal ID purposes, like boarding airplanes.
Seems reasonable.
Nothing. It's just a rider attached to the Intelligence Overhaul bill. This has been going on for about 200 years. People (Senator Byrd comes to mind) attach an item in some unrelated bill and the President must accept the rider or kill the whole bill.