One broader lesson people need to take away from the legal wrangling over the Arizona law: Any enforcement provisions of "comprehensive immigration reform" that Congress might pass would be tied up in the courts for years. As my colleague Steve Camarota wrote recently:
Any employer verification system will be challenged in court. So will any efforts to coordinate immigration enforcement with local police. Immigration lawyers also will fight every effort to detain more of their clients. Building new fencing and dealing with environmental and property rights issues at the border will involve legal battles. While in time these things almost certainly will pass legal muster, court injunctions and proceedings will hold up enforcement for years.
So while the amnesty would go into effect immediately (because, after all, the ACLU supports amnesty), the other provisions, regarding E-Verify and border enforcement and the like, wouldn't go into effect for years, if ever. So almost by definition there can be no grand bargain of amnesty (and increased immigration) in exchange for tougher enforcement; the enforcement must not only be legislated before any discussion of amnesty, it must be fully litigated, too.