Nobody said ICBMs. USAF has a Global Strike Command which handles the nukes which are delivered by aircraft and/or cruise missile. Tactical or Theater weapons with smaller explosive yield, not the high-level Strategic weapons.
Besides, it’s a little late for us to do a “first strike”.
Let’s see what the tonnage put into orbit looks like if reusable rockets pan out. Rail-guns are nice; but, Thor would really make a statement. “Rods from God” are not prohibited by any current treaty.
You forgot the “Boomer” fleet, the sub launched missiles, & as far as I know they are always up and ready to fly at a moments notice.