Hypersonic weapons are becoming the new thing, I think nukes might actually get phased out. Nukes run the risk of getting shot down,since they're still ballistic trajectory, hypersonics will be entering with extreme velocity and high maneuverability that make them virtually impossible to take out. The end goal is a decapitation attack on a state capital or critical resources. Nukes are one way to do it, but a hypersonic weapon moving so fast you can't possibly shoot it down is an attractive option. They don't even need to pack that much explosive at the speeds they're going at, the raw kinetic energy itself is already scary enough. It's a bit more unnerving because a hypersonic strike will give you much much less warning than a nuke (if any warning at alll), but at least there won't be any fallout. Dead man mechanisms might cause a massive retaliation strike though.