For a while the trend has been towards smaller nukes (called tactical nukes), not bigger ones like in the 60s. The rational being that smaller, more precise nuk

For a while the trend has been towards smaller nukes (called tactical nukes), not bigger ones like in the 60s. The rational being that smaller, more precise nukes have a lower threshold of usability. Destroying Beijing and killing 20M people is a solution of last recourse, and would be disproportionate in retaliation to a tactical nuke, or a conventional attack resulting in massive casualties. One reference I could find: https://www.theguardian.com/us-news/2018/jan/09/us-to-loosen-nuclear-weapons-policy-and-develop-more-usable-warheads https://www.theguardian.com/us-news/2018/jan/09/us-to-loosen... [EDIT] Of course even these tactical nukes are way more powerful than the ones dropped on Hiroshima and Nagasaki.