Being Bombastic.

This is what Donald Trump is known for and, in fact, it is his defining feature. Recall his, now famous, "very smart missiles", or him touting his economic "achievements" non-stop. Exiting crucial arms limitation treaties is also a part of Trump's MO, such as ditching Open Skies Treaty and now promising to resume testing of nuclear weapons:

US authorities considered whether to carry out a "rapid" nuclear test – the first for almost three decades – to use as a bargaining chip in dealing with Russia and China, according to media reports.The proposal to cause a controlled nuclear explosion is "very much an ongoing conversation," a high-ranked official within the administration of Donald Trump told the Washington Post on Saturday. It was assumed that a "rapid test" could prove useful in making Moscow and Beijing negotiate a nuclear-weapons-related trilateral deal with Washington, the paper's sources said.

As is observed by many, often being bombastic is a cover for the lack of strength and substance. We have exactly this case here exacerbated with a very low level of understanding of modern geopolitics and international relations by US "authorities". They, those "authorities" want to abandon a 1996 Comprehensive Test Ban Treaty CTBT), evidently, based on this clause:

Each State Party has the right to withdraw from the CTBT if it decides that extraordinary events related to the subject matter of the Treaty have jeopardized the State Party's supreme national interests.    

One may ask, then, upon discounting totally delusional assumption of those "authorities" that Russia will tremble in horror and will offer an unconditional surrender upon US exploding some device, and what those "supreme national interests" might be? The answer, apart from Trump's propensity to do a lot of chest thumping, is simple enough:

1. Nuclear weapons are not war-fighting weapons but are primarily deterrents to avoid a war;

2. Nuclear weapons are considered the last resort weapons and by all metrics, as is a terrorism, are weapons of a weaker side. 

Recall what I wrote two years ago when speaking about China:

China is (relatively) weak militarily NOT because she doesn't have enough nuclear weapons—this could relatively fast, with Chinese financial wherewithal, be addressed. Chinese relative military weakness comes from a huge technological, cultural and organizational issues of her conventional capability, which, despite its polished outward appearance,is nowhere near with that of the United States or Russia. It is technology—always was, always will be. It is also an operational experience and the way conventional forces are deployed, which matters great deal—China has no real operational experience here. There are reasons to believe that some technological gaps will never be closed—China continues to struggle mightily in aviation, submarine, space technology and other key technological and operational concepts. 

This applies fully to the United States today who lost a conventional arms race finding herself a generation or two behind Russia in technologies which are in foundation of the Real Revolution In Military Affairs. It is preposterous to even contemplate the fate of US (NATO) forces in Europe, let alone in the immediate geographic vicinity of Russia, in case some "authorities" in the US decide to commit a suicide and attack Russia. NATO forces and their decision centers will be dramatically degraded and ultimately defeated without the use by Russia of any nuclear weapons. That is not me talking, even RAND's big honchos admit that. In this case abandoning CTBT is merely another manifestation of Trump Admin's bombastic style, designed to cover up for the fact of a loss of the conventional arms race. Luckily, not all "authorities" in D.C. are bat shit crazy and some real professionals made their voices heard:

“There are still some professionals in the room who told them this is a terrible idea, thank God,” an unnamed congressional aide told the Guardian.

But, the truth to be told, it doesn't matter. Already in late 1970s Soviet military thinkers considered Stand-off High Precision weapons approaching levels of operational and strategic impact close to nuclear weapons. Today, in the age of hypersonic missiles, combat networks, advanced electronic countermeasures and instant propagation of tactical, operational and strategic information, and instant decision-making, we are looking at the warfare of unprecedented precision and violence. In the end, who is to say that Poseidon is only for delivering a nuclear payload? With the internal volume capable to accommodate a monstrous payload of the conventional explosives, this system will have little trouble reaching and positioning itself underneath a keel of the aircraft carrier and literally blowing her out of the water without any nukes. So, resumption of nuclear testing may only create a sense of amusement in Moscow, whose nuclear and, especially, conventional war-making potential keeps the US from unleashing conflicts all over the globe. As per being bombastic--old news.

P.S. In related news:

The New and Improved Tomahawk Missile Now Runs on Corn

That, sure as hell, should make those nasty Russkie Ivans and Chinks tremble in horror. Did they try to build a new missile? No? Well, there you go....