NAFTA has long had a provision to allow for the free movement on "professional" employees under the following circumstances:
1. A job transfer within a company operating in both countries.
2. A written job offer and "proof of qualification", such as a degree.
American headhunters in the computer industry love it because there is no quota on the visas and they don't have to jump through hoops to convince the INS that they couldn't find a yank for the job.