Under our current laws, a POTUS could order a nuclear preemptive strike without Congressional approval.
That should make people feel uneasy about how much power Congress has rescinded.
As to ideal future state: I suppose I have a bad imagination because I can't think of a scenario where the President has to emergency order a preemptive nuclear strike without waiting an hour or less for Congressional approval.
Agreed, but that has always been the case. That is not a power that Congress has rescinded in any way. Anyhow, the second point is that you don't have to imagine a scenario, because there's nothing stopping any POTUS from acting unilaterally to start a nuclear war.
Imagine POTUS receives intel that China is goading North Korea into launching a limited nuclear strike against our allies in West Pac. Upon launch warning, POTUS decides to launch a retaliatory strike against NK and China. Many would argue that goes beyond self defense. Does POTUS have a constitutional duty to get the Congress to authorize a major escalation?
The use of nukes is that one caveat to the normal process of properly authorizing force. We've talked ourselves into it being in a special category because of the Cold War need for rapid action in self-defense, but we've overlooked the potential for non-self defense use of nukes, for which there is virtually zero checks on the President's power to wage the most serious kind of warfare. Short of a constitutional amendment, I don't think there's a way to change that.