Here's part of the Senate debate where they discuss it. It turns out that they were extremely precise about what it meant, and they described the exceptions in great detail. It's even typewritten. The downside: you can't come away from reading this stuff and pretend like there's some legal flexibility in the term. If that's important to you, you probably shouldn't click the link.

[1] https://digital.library.unt.edu/ark:/67531/metadc30867/m1/12...