Would it be legal to add "Have you ever worked for the NSA?" to your interviewing questions? I'd like to see them all denied jobs in the private sector once they lose their jobs with the NSA. They have knowingly worked to support spying on American citizens. Treat them like the criminals they are.
While we're at it, ask if they worked for SCO over it's last 5 years... don't want that so called 'talent' to ever have an IT job again, either.
Would it be legal to form a do-not hire list based on previous employment? It's not a race, it's not a sexual preference, it's not a gender... It's an indicator of ethics.
What's good for the goose is good for the gander.
Living on Earth may be expensive, but it includes an annual free trip around the Sun.