It can protect your career when you are being asked to do something that might be illegal. Especially if you have a security clearance of some sort and it would violate it.

This might be an important distinction between ethical and moral. Standing up against unethical behavior protects one career, but if the behavior is ethical but immoral (that is to say, it violates your own standards but is deemed acceptable in the larger community) then it doesn't really protect one's career. But the self image protection might still be worth it.