Secure

I've got two small kids here, both of whom like Thomas the Tank Engine. On the left, you'll see part of one of their presents - a coal car. Like all toys these days, it's strapped in so securely that it's often easier to get a pair of wire cutters than try to undo the Gordian knots holding the thing in. If our nuclear arsenal is this securely locked down, we've got nothing to worry about.