I agree with Amos. For questionable benefits the possibilities for abuse are ominous.
There is already a movement in Congress to limit the use of personal information collected by businesses.
What happens when a national ID card is required to be used routinely (else why have one) and the information collected is fed into a central database. And stays there.
The temptation to use the information for anything from the war on drugs to profiling to catching underage drinking would be a powerful one. And not to be used in Court but used unofficially to figure out who to put under surveillance for various crimes having nothing to do with terroism.