Prof Blaxland added: "To be fair, Trump's much more assertive nuclear posture comes at a time when Russian Federation and China have themselves considerably expanded and modernised their arsenals and when North Korea has brought the issue back onto our TV screens and news feed headlines".
What is the U.S. doing to its nuclear weapons?
First, it would modify "a small number" of existing long-range ballistic missiles carried by Trident strategic submarines to fit them with smaller-yield nuclear warheads.
The new policy - the first update of the Nuclear Posture Review since 2010 - pushes modernization of US nuclear weapons, infrastructure and delivery systems.
"Meanwhile, successive United States administrations deferred much-needed modernization of our nuclear weapons, infrastructure, and delivery systems".
To drive home the point about deterrence, and to make America's ability and willingness to respond to both nuclear and non-nuclear Russian attacks more "credible", the Trump administration plans to pursue the first new nuclear weapon systems since the Cold War. Low crisis stability reflects a condition when leaders feel pressure to respond quickly even to ambiguous events because the risk of inaction may be greater than the consequences of acting inappropriately.
He said it was also long-standing USA policy to "maintain some ambiguity" on when the US would use nuclear weapons.
South Korea is a major U.S. ally with the two countries forging strong military and economic ties.
Lifetime of polar bears captured on collar cameras
While four bears put on weight, five bears lost up to 10 per cent of their body weight - between 18 and 20 kg - in 10 days. Data shows from 2004 to 2007 polar bears population in the Beaufort Sea has been gone down by 40 percent.
North Korea was also mentioned in the review, with the United States describing it as a "clear and grave threat".
"There is no scenario in which the Kim regime could employ nuclear weapons and survive", the NPR said. It asserts that any North Korean nuclear attack against the US or its allies will result in "the end of that regime".
"There is no indication from public information that Russian Federation is actively developing the system, but it is alarming to see it in a Pentagon document", Mount said, adding that while the program is referenced in the Nuclear Posture Review, it is not mentioned in other government reports.
In making the case for modernizing the triad, the NPR stated that the US for decades led efforts at eat nuclear arms reduction worldwide and the efforts accelerated with the fall of the Soviet Union.
"There are no good nukes and no such thing as a limited nuclear war".
The Trump administration concluded that the US should largely follow its predecessor's blueprint for modernizing the nuclear arsenal, including new bomber aircraft, submarines and land-based missiles. This postulates that Russian Federation would threaten the use of tactical nuclear weapons to bring to an end a military confrontation with the West it feared eventually losing.
"We must look reality in the eye and see the world as it is, not as we wish it to be", the NPR said, "given the range of potential adversaries, their capabilities and strategic objectives".
Two weeks ago, Mr Mount said the leaked review translates Mr Trump's impulses into an order for new, more usable nuclear options.
The latest thinking was revealed in a Pentagon policy statement known as the Nuclear Posture Review (NPR). That is why the Trump administration must modernize the USA nuclear arsenal and warheads. The U.S. says it has been in compliance with the limits since August and it expects the Russians to comply by Monday's deadline.