The same political problem exists with SLBM's if we are talkingTrident. The deterrent is NOT directed at Russia.
Is there some technical reason that we are unaware of that Trident missiles cannot be aimed anywhere other than Russia?
The problem is not with the missile, it is with the flight path over the pole and Russia. Trident missiles should not pose a problem as long as they from the southern India Ocean for Iran, India, and Pakistan targets. North Korea is a bit trickier due to the proximity of China, but probably near Australia would be suitable launch location.
The deterrent is directed at Iran, India, Pakistan, and North Korea. Let's be clear and cut through the mud. These countries are not going to be able to field antiballistic missile batteries with any genuine competence any time soon.
Anyone of them could purchase Russian S-400 any day if not blocked by sanctions (Iran). The S-400 is supposed to be equivalent of Patriot system, but longer ranged. China supposedly has a similar system going into production, and no interest in abiding with sanctions. The S-500 system, when it hits the market, is supposed to have capabilities closer to the THAAD system, and be able to stop anything slower than an ICBM.
India is actively negotiating to purchase production capability for either the S-400 or the Israeli Arrow system. Pakistan has over 100 nukes, all aimed at India, so they are obviously highly motivated and hope to build a lot of them quick! When they do, Pakistan will probably follow suit.
They would be decimated by theater ballistic missiles TBM's, if they existed in the region, in short order. it is a deterrent. Even if they HAD ABM assets, taking a chance they could stop a couple far outweighs the likely destruction.
Given that these are mobile systems you are trying to kill, and are deploying camouflage and decoys, history has shown that will be extremely difficult. Still, if you are using nuclear TBM to kill the ABM system to clear the way for a nuclear TBM strike on your target, ...
The issue is these countries do not believe the US would respond with strategic ICBM's for a regional nuclear launch against regional enemies. The question is, if the US had TBM's positioned regionally, would that be a deterrent or not? Well I don't know... which is why I am asking.
I don’t see why those countries should believe that if they initiate a nuclear exchange that the ICBMs and SLBMs will not be deployed in response, it is established policy. The use of WMDs is not a military decision, but a political one. If US troops are nuked then whatever system can penetrate RIGHT NOW will be the one used. The politicians cannot afford to look ineffective (political suicide) by waiting for a slow neutralization of the defenses to clear the way, especially if there is the possibility of further use by the other side.
And then there is another political question – Which countries are you going to base the TBMs in? There are not any US nuclear weapons currently based outside the US except possibly a couple not yet removed from NATO bases in Europe. Which new countries to you envision accepting US controlled nuclear weapons being stationed on their territory?