Imagine China fired all her nukes at the US and the US retaliated while the Chinese ones were in the air... there would be nothing left of either country within a couple of hours (or however long it takes to reach across the globe).
Anything left would be uninhabitable forever.
I dunno... nukes are messy.
E-warfare is "clean" and costs practically nothing to do.
2: Tactical (not strategic) nuclear weapons are very likely to be used on the battlefield in the next major conflict involving the superpowers. The most plausible pathway to a nuclear armageddon is if the number and yield of these tactical weapons keeps escalating until one side finally has enough and launches a strategic strike.
I'm not sure that's entirely true. Even if DC gets nuked before it can react, I'm pretty sure there are dead man switch-type systems in place and stuff like submarines equipped with nukes away from home so that even if they whole country was glassed there would be some retaliation. These scenarios probably don't reflect the whole arsenal, so the retaliation wouldn't hit every square inch of the enemy's land, but I would still think that threat is enough to make you not want to start anything.
Check.
There's a pretty good argument that democracy is possible because of the existence of guns. In medieval time, a peasant with a pitchfork stood no chance against a knight who'd been training his whole life and had all the tools of warfare.
These days, an angry mob of people with guns can do quite a bit of damage. The US military couldn't even beat the Viet Kong, despite how woefully inept they were at the start of the war, because they were determined not to surrender.
However, if future combat is all automated, we're back to the feudal days where all it takes to win a war is having more money than the next guy. A future Jeff Bezos could buy his own drone army and exert as much power as many national governments.
Now instead of having humans inside machines fighting other humans inside machines, it'll mostly be machines fighting machines. And yes, they'll be devastatingly effective against just humans but that's already the case with non-autonomous machines.
Autonomous weapons are a step on the existing tech advancement = force multiplier curve, I don't think they're fundamentally doctrine-changing. Like someone else commented here before, the actual game changer weapons will probably be biological. Unlike autonomous drones/tanks/whatever, advanced biological weapons will soon become available to just about any two bit state actor. Very little thought has been given towards defending against such attacks.