n. The process of reducing or ending the protection that a group, thing, or action receives under a constitution.
2002
Deconstitutionalization simply means that those who live between the Rio Grande and Border Patrol's secondary checkpoints live by a different set of rules. With narcotics trafficking declared a national security issue, the courts are holding the police and the military to very limited standards regarding protection of civilian civil liberties. Border residents are much more likely to be pulled over and subjected to random warrantless searches.
2001 (earliest)
Even war as a metaphor — the war on drugs, for example — can have a dramatic, and unequal, effect on civil liberties, as shown by the recent revelations of how widespread racial profiling had become before the public even had a name for the practice. 'You fly the metaphor of war, and constitutional protections all cut in one direction,' said Dennis J. Hutchinson, a law professor and historian at the University of Chicago. He said the 'deconstitutionalization of the automobile' — the ever wider discretion for police searches for drugs — 'is the most obvious recent example of panic moving the terms of discourse.'
This word has been used in law circles for quite some time (since at least the 1940s), but I believe the earliest citation marks its first appearance in the mainstream print media.