Alex, the trouble with nuclear weapons is they cannot be used without the user suffering great loss from retaliation from those that also have them, as well as suffering political backlash if used against those that don't
But if it were the case that they could use them without suffering a foul, then they probably would. Nuclear bunker busters would be a no brainer...
I highly recommend a non fiction book by the title: Mandela's Nuclear Nightmare - Peter Hounam.
It lays out a fairly compelling case that the fourth generation nuclear weapons (which Sam Cohen alluded to) are in fact real.
These are pure fusion devices that do not require a critical mass of fissile material to trigger them.
There are 3 points of note that should be of great concern to everyone:
They don't leave any radioactive contamination behind, so there is no public backlash / political consequences in that respect.
They are 3 orders of magnitude easier to construct than a fission device, and the materials would be trivially simple to obtain for any government or large corporation that chose to do so.
Third point, the yield can be as small as a couple of tonnes of TNT... so hypothetically, for example you could set one off in the main street of a city and blame it on ISIS to justify an otherwise unjustifiable war on a country you didn't like... Iraq, Syria, Libya, Iran... pick one.
Some argue that the (second) Bali bomb fits this description (I don't know)
What I do NOT believe is that the damage caused by the Bali bomb is consistent with a van loaded with anfo.... it had to be nothing less than the highest end military explosives at the very least. Therefore, it must have been state based terrorism riding shotgun behind the veil of their Jemaah Islamiah patsies.
Qui Bono?
Anyway, if we work on the premise that 4th generation nukes are in fact real and deployed, then we consider that a nation state could use them and get away with it... For example, you could bomb a target in a city in some middle eastern country, and if someone was lucky enough to catch it on tape... No western media outlet would actually run the footage. But even if they did break ranks and aired it, then it could be explained away as an ammunitions dump going off... or just blame it on the Russians.
The conclusion then is that you can bet your house that it is only a matter of time before some bunch of nutters, somewhere, will try and win a war that way..
For what it is worth, there has been some serious shenanigans going on in Yemen & Syria over the last couple of years... and none of it reaches us via the western media... I wonder why?
Watch the following explosions.. I don't make any claim with respect to what caused them, other than that these do not look like Jdams to me.
https://www.youtube.com/watch?v=OTE_Eshm2xw
https://www.youtube.com/watch?v=KoRIWXpHoxg
https://www.youtube.com/watch?v=vm7ObVSix7w
https://www.youtube.com/watch?v=MS4jIqV5zDU
Cosmic ray hits on the CCD?
Lightening in the mushroom cloud...?