Job security is an oxymoron because in the new economy there is no such thing as a safe, secure job. You may have a job, but it's not secure.
The idea of a safe, secure job can be compared to a mirage. You struggle through the desert of employment, hot, tired, frustrated, thinking, "Just a little farther and then I'll be there." Where? Retirement. Comfort. A life of ease to make up for all those years of sticking it out. And then, after years of toil, bad supervisors, impersonal bureaucracy, underemployment, working for "the man" you discover that the mirage keeps getting farther away, or disappears altogether.
I'd be mad if this happened to me, wouldn't you?
So what do you do to prevent this from happening to you? Don't assume your job is secure. Value it for now for what it is but don't take it for granted. Have a backup plan in place. Cultivate your network. Build a strong reputation for yourself. Be the kind of person that others will jump to hire if you suddenly become available (i.e., laid off). And, of course, learn how to operate in the B and I side of the CASHFLOW quadrant so that you can have money working for you... instead of the other way around.
If you do this then you don't need to worry about job security... you won't need it.