Maverick's World

2) "Publicly closing off diplomatic exit ramps" - this is more obvious - if the nation being targeted in President Trump twitter trolling feels that it has nothing to gain from diplomacy, it will be pushed into a nuclear "use or lose" situation and the is almost no way to avoid using nuclear weapons at this point.

There is one more scenario that I feel Jeffrey Lewis seems to have missed.

Deterrence at its core relies on the notion of the adversary being a rational actor. This is perhaps the most questionable part of the whole deterrence process - and naturally national security communities everywhere have large sections that push back against it. 

In order for this to actually work one needs to be able to make a determination that the adversary is not irrational. If no such determination can be made - then one ends up in a very very dark place. You simply cannot determine if a threat is emergent and so your instinct is to raise your readiness levels. Once you operate at higher readiness levels, you open yourself to misuse or accidental release mishaps and your adversary might read your actions as a hostile intentions and put their own forces at a higher level of readiness. The situation can quickly creep up the escalation ladder before corrective measures kick in. 

Whether we like it or not - all intelligence gathering is a matter of polling and averaging (or perhaps more correctly statistical modeling). Most agencies prefer to do these polls and models in an explicit fashion, although every intelligence officer at some point of time uses their own personal judgement to determine whether the intelligence estimate is reliable. There is no magic bullet and all data is averaged in building up an estimate. That is why even a twitter feed can become part of an estimate. If you don't believe me ask all the financial analysts that are now trying to figure out how to capture the "twitter-risk" to their stocks. This problem is particularly acute in the case of Donald Trump's twitter account as he uses the account as his personal communication space. It automatically feeds directly into the intelligence estimates of all our adversaries - including traditional foes like Russia. 

During the campaign it has been noted that Donald Trump frequently reversed his positions on key issues, and displayed an amazing lack of comprehension and coherence on nuclear weapons issues. His supporters saw this as a sign that he had some savant level understanding of things, his detractors pointed out that this is exactly a way a bullshit artist behaves. 

Now that he is no longer campaigning and still doing all manner of flip-flopping, his supporters are bewildered. His detractors see something more sinister at play. (for example he said he had a secret plan to fight ISIS - he had none - his landing team in the DoD asked the officials there to prepare one. His supporters have fallen remarkably silent on this - his detractors are saying he will declare a war on ISIS to seize control of executive powers currently outside his reach.) .

President Trump's flip-flopping may be "just politics" (whatever that is) - but any rational SVR-RF and GRU analyst would be within their rights to wonder if President Trump is a rational actor. By questioning his rationality, these analysts could call into question the stability of the US-RU deterrence regime. 

As long as President Putin is in power - he will be able to hold the voices of dissent inside Russia's intelligence community at bay. If he is unable to do so - or is removed from power, the RU will move its nuclear strike forces to a maximum lever of alert.  

The closest historical analog to this is the early 80s - when President Reagan's irresponsible campaign rhetoric put the world at the edge of a nuclear sword. And the worst part was that Reagan and the USIC really didn't know how close it came. Only after the USSR fell - did the terrible secret of Able Archer become known. As Chairman Andropov lay dying in hospital and the final hours of Able Archer dragged on, the Russian military asked for powers to move and launch nuclear weapons without direct Kremlin authorization as clearly nuclear war was imminent. 

Most people don't know the story of Able Archer. It is too terrifying for a greater portion of people to even begin to comprehend in its entirety.