Nukes really don't destroy that much land directly, the difference with nuclear war over regular ones is mostly just the fallout.

The people intuitively scale up Hiroshima and say it's 1,000x as strong so it destroys 1,000x the area. But, it's non linear the giant hot ball of gas quickly gains altitude. Sure, the center get's more energy but it was destroyed anyway.

Also, the atmosphere cuts radiation exponentially with distance. So, if you block 1/2 the radiation at X, then you get 1/4 at 2x and 1/8th at 3x. Thus doubling only increases the lethal radius by X rather than say 5x which is the original lethal radius. (Note it's more complex as radius also reduces the received dose directly, and radiation turns into heat etc.)

PS: You can estimate direct damage as ~10000 * ~100 square miles (most nukes are sub 1MT) ~= 1 million square miles. But, the earth has 57 million square miles of land. So ~2% of total land though much of this would be over water as many cities are coastal. So, if you could ignore fallout and each nuke was targeting something else most land would still be untouched.

Now we just need to work on not targeting civilians, not destroying the electrical grid, minimizing fallout etc.

Yes, and Khrushev singlehandedly conducted a psy-op, ingraining the concept of "missile gap" into psyche of American political establishment.

At the time when ICBMs were still toy weapons, he successfully pushed NATO nations into spending enormous resources bringing up their strategic nuclear forces, while the bloc was popping T55s by thousands every week.

On a macro scale, all an every "lateral movements" were nothing but a ruse, disguising the fact that the only strategy he had was to send a patently enormous mechanised force over a wide front.

The more remarkable was, that, I think, that every military analyst pentagon had was coming to this very conclusion very easy, but none of them were ever heard in white house or by higher up generals.

Big name generals were themselves convinced that all of that itself was a ruse, and that Khrushev had a secret joker in his pocket, and that he will not resort to the most straightforward way to defeat them.

And American presidents, of course, only wanted to hear an opinion that was easier to believe in, coinciding with their own view of the world. What they believed in? They believed in a vision of a clean and fast war, where enemies are instantly vapourised at a click of a big red button.

The military efficiency is quite similar, however, the destructive power has dropped significantly - these targeting improvements resulted in much less powerful warheads being necessary to achieve the same goal, so not only there's much, much less warheads (10000 vs 60000 at the height of cold war, and "only" 3000 of those 10000 are available at short notice) but also each warhead is much less destructive, the "default" warheads have gone down from multiple megatons to 100-150 kilotons.

This means that an all-out war will not only have much less fallout than in 70s, but also much less civilian casualties, much less destruction of cities, etc, etc. In the 70s, if a military base near a city would be targeted, then the city would be eliminated along with the base; now it'd likely be targeted with just something like 100kt bomb with much smaller impact; if the target was in the middle of the city, then most of the city would survive.

For a period accuracy on ICBMs wasn't very great (on the order of a kilometer), which is why they made use of very high yield weapons in the several megaton range. Large warheads were necessary to take out targets (such as population centers) with those accuracy levels. Then several things changed: accuracy improved greatly, the ability to put multiple warheads on a single missile arrived (MIRVing), and anti-ballistic missile defense (ABM) started taking off. This lead to the use of more, higher accuracy, lower yield warheads to take out targets. You could blanket a city with sub-megaton MIRVed warheads instead of using one big 10 megaton bomb. And then the calculus of "but how many will be lost to the ABM systems?" came into play, which resulted in use of "penetration aids" like decoys as well as the deployment of vast numbers of warheads to ensure enough of them made it through. That led to a massive rapid escalation in warhead deployment during the '60s and '70s until the ABM treaty flattened it out.

But this is only half the story. The other half is the massive deployment of tactical (battlefield) nukes. With the invention of smaller nuclear warheads combined with the massive production capability of the weapons procurement pipelines in the US and USSR it became possible to deploy tens of thousands of tactical warheads. These would be used for everything from anti-ship missiles and torpedoes to anti-aircraft weapons to short range ground strike missiles.

The late Cold War and post Cold War arms limitations significantly reduced the deployed number of warheads of both the US and USSR. They massively curtailed the number of tactical nukes deployed, and they resulted in a lot of "de-MIRVing" of missiles. A modern Ohio-class nuclear missile submarine can carry 24 missiles each of which can carry up to 12 W-88 (475 Kt) warheads. Potentially that's up to 288 warheads and over 130 megatons of total destructive power, basically WWIII in a can. However, today they carry far fewer warheads than that due to treaty limitations. Similarly, most of our land based ICBMs have been de-MIRVed and we've retired new weapons systems (like the MX/Peacekeeper) which were heavily MIRVed.

All of this has translated into far fewer warheads in service or on alert and a much reduced overall destructive capability. It is still an overwhelmingly enormous nuclear destructive capability but it has been reduced significantly through treaty obligations over the years.

Don’t confuse the development of guided conventional munitions with nuclear ones it’s a completely different ball game.

Costs and size don’t mean much for nukes, nukes also can’t use GPS, CCD sensor or any other “modern” guidance system due to reentry and many other factors.

Because the US will disable GPS for everyone but their own forces in a heartbeat in the event of war.

And China / Russia might be able to knock out US GPS pretty quickly - but all of that is very untested, moreover, the US may have a way to put up a bunch more satellites quickly.

Systems today have become really, really dependant on technologies that may not be available in a time of war.

It may very well could be that if the US has their act together they could shut down an advanced opponent pretty quickly without having to do much at all.

I'm actually pretty curious as to how advanced guidance systems would work in 2018 without GPS like technologies, not just in 'known tech' but behind the scenes, all the secret stuff.

It's hard because in some ways we could expect them to be way, way ahead with some things, but in others, they might be blindingly incompetent, for example, maybe the US really doesn't have a plan for rapidly popping up new GPS satellites in the event the Chinese knock some down.

If Russia decides it's time to annex the entire country, on the other hand...