How do you stop a sovereign nation from making a nuke. You cannot!!! It is their sovereign right to do so. Telling them they cannot is seen by many nations in the world as US hypocracy. Only the US can have nukes and no one else can?!!!! Is the US trying to dominate the world??!!!! That is the narrative our opponents use to great effect. I propose a different way to deal with Iran, North Korea and their backers. If China wants to help NK, fine, the US should encourage Japan and South Korea to build nukes. If the US wants to stick it to China, tell Japan to transfer technology to Taiwan to build nukes. In other words spread nuclear technologies to anti China and anti Russian nations. Two can play the same game.