If you'd left it at the first sentence I'd have read it as nicely pitched sarcasm. If it's a single Hiroshima scale device, sure, it'll probably help some. If

If you'd left it at the first sentence I'd have read it as nicely pitched sarcasm. If it's a single Hiroshima scale device, sure, it'll probably help some. If countries are exchanging their deterrent missiles, no, you're not going to avoid 90% of the deaths.