"Biometric identification isn't the only way of securing a weapon."
It's not even a good one.
The problem is not that such identification technology is impossible. The problem is that it is impossible to make it that reliable with today's technology, while still being able to perform its security function (keeping the bad guys from using the gun). You can have one, or you can have the other, but so far -- despite several products that have been hyped -- nobody has come even close to doing both. You have to have both or it's worse than useless, because it will get good people killed.
"A police officer could be issued a gun with a RF component in it that operated around 800 MHz or so. At this frequency, the signal clings to a person's skin and clothing. A low-power, short-range transmitter, perhaps embedded in the officer's radio, could complete the circuit. Thus if the officer was not in physical contact with the gun, it wouldn't fire."
If it were that simple, it would be done already. For one thing, RF is FAR too easy to foil. People have been experimenting with that kind of technology for many years now, and not one has come even close to putting one on the market. Again, the main reason is maintaining reliability and security at the same time. One or the other is relatively easy. Both are not.
"... nothing in what I've said is either for or against whatever political cause or position you're advocating. t is simply, and purely, an engineering analysis. "
It's not even a good one.
Sorry to have to say that, but in good conscience I have to say that. You ignored some rather gaping holes in the problem domain. But don't feel bad; even the makers of safes and other security equipment famously suffer from tunnel vision in that regard. For example: in recent years not one but many manufacturers of safes with electronic combination locks focused on the security of the electronic lock but paid little attention to the physcial locking mechanism. As a result, one security researcher produced a YouTube video of his 4-year-old, with no knowledge of the combination, opening some of them with ease.
Security vulnerabilities surround everything we do. It behooves one to step back and look at the larger picture. We are not yet even close to the technology required to put reliable and secure "lockout" mechanisms on guns. At the moment it's still science fiction. Biometric identification is not the problem. The problem is making it absolutely reliable, while ALSO rejecting the unauthorized.