A warning of a nuclear missile launch is about the most monumental warning of any sort that could be issued in these days and times. What amazes me most about this entire affair is that a nuclear warning system of any sort exists that can be initiated by only one person. I thought there’d be multiple checks by more than one person for anything of this magnitude, but apparently not.
Possibly you're confusing a warning with a retaliatory strike. In the latter case, yeah, we'd better hope that "a system is in place."
In the "warning" case, We have implicitly assumed, I believe, that this was only to be issued by a centralized national agency, to be assumed authoritative.
To me, the mystery is how the "Hawaii Defense Department" has the authority, or the capability to issue such a warning, without authorization or instruction by a Federal agency.