I’m not sure if hypersonic missiles or Iran’s drones have a chance of first strike capability. If so, or if some countries will think so, and/or don’t fear a second strike, then we need to take preventative steps. The same applies to nuclear weapons (with or without these) and perhaps likewise even poison gas.
If there is a chance of conquest by China, Iran or North Korea—or a chance of destruction by any of those countries or by Russia, we need a freeze on new missiles and/or weapons of those sorts; there should be immediate inspection of any suspicious sites in order to verify this. (If they don’t fear a second strike, or would furnish to terrorists, we need to have them dismantle what they already have—again with immediate inspection.)
Perhaps the way to do this is by offering and/or establishing increased trade while threatening increased sanctions, with the spread wide enough so that they won’t want to chance our missing any of the sites.
For Russia, we might also try diplomacy like a NATO invitation. Alternatively, increased economic ties might forestall destruction. For North Korea, perhaps we might also give them a choice between de-nuclearizing the Korean peninsula or putting enough arms in South Korea and nearby to destroy them.
Perhaps we can bring about human rights, such as freedom of religion; and perhaps we can get China to stop supporting North Korea if nothing else works with the latter.