Trump's national security adviser John Bolton is a 'hammer and he sees everything as a nail'

President Donald Trump's new National Security Adviser John Bolton is a diplomatic “hammer" who "sees everything as a nail,” according to experts.

Mr Bolton replaces the more measured General HR McMaster and joins erstwhile CIA Director Mike Pompeo, the president’s nominee for to replace former Secretary of State Rex Tillerson, as part of a new more war-focused Cabinet.

Juliette Kayyem, a professor at Harvard University former Obama-era official in the Department of Homeland Security, told The Independent that the “Pentagon-styled” Mr Bolton “seems [to see] the military as the solution to all threats and it seems inconceivable he can change that opinion”. The moustachioed former diplomat under the administration of former President George W Bush became known for his intractable views on beginning the Iraq War, defying the United Nations.

As national security adviser, Mr McMaster was “extremely knowledgeable not only in military practice but military history and the impacts of war,” according to retired US Army Lieutenant Colonel Danny Davis, who had served with Mr McMaster during the first Gulf War.

“Stabilising force” were the words one New York Times column used to describe Mr McMaster, which also said his presence would balance “the hot heads who occupy Mr. Trump’s inner circle”.

Mr McMaster was part of what experts called the “axis of adults” that was dubbed as such to reign in and guide an inexperienced Mr Trump in the areas of diplomacy and military matters. After Mr Tillerson’s public sacking on Twitter and the Mr McMaster’s long-rumoured departure, Defence Secretary James Mattis is the only one left.

Whether the former Marine General and Mr Bolton will work together well is a concern, said Mr Davis and may require “refereeing” on the part of the president. It is a skill for which Mr Trump is not well known. The key will be for Mr Bolton to stay out of the purview and areas of responsibility of the Defence Department and Pentagon.

Mr Davis noted that Mr Bolton, who served in the Maryland National Guard and US Army Reserves towards the tail end of the Vietnam War, does not actually understand or is perhaps unwilling to consider, the impacts of war. He “almost rejects diplomacy,” Mr Davis said, despite his experience as a former US Ambassador to the United Nations.

Even the relationship with Mr Trump, who “clicks on a personal level” with Mr Bolton, could be akin to walking on a tightrope, Mr Davis said. He noted that the pair are “two big, type-A personalities” and all is well when they “happen to see eye to eye” at this point. What happens when they do not could lead to “friction” in an already drama-filled White House and term in office.

Beyond potential personality clashes, the President’s appointment of Mr Bolton is a demonstration of the US becoming “less likely to take into consideration the needs of our allies as they make policy,” Mieke Eoyang, Vice President for the National Security Program at DC-based think tank Third Way, told The Independent

Of particular concern to foreign policy experts is the upcoming meeting between Mr Trump and North Korean leader Kim Jong-un to discuss the possible denuclearisation of the rouge state. Mr Bolton has spent years advocating for wholesale, and inevitably violent, regime change in North Korea and Iran.

Vipin Narang, a political science scholar at the Massachusetts Institute of Technology, tweeted “Did people revise the probability of war up after the announcement? If so, how much? What is the “Bolton effect”? I’ll start: 4x revision up from 5 to 20 per cent”. Ms Eoyang said she thinks the North Korea negotiations are also now “less likely to include South Korea and Japan, our traditional allies” in the region and the meeting will likely not lead to “an outcome that leads to a peaceful resolution of tensions”.

Others worry that Mr Bolton will act as more of a shill for Mr Trump's own views rather than simply an advisor, which could lead to disastrous consequences with that concern also extending to Mr Pompeo.

As a member of the House of Representatives, Mr Pompeo defended the CIA's use of torture during former George W Bush's administration, saying: “These men and women are not torturers, they are patriots...the programmes being used were within the law, within the Constitution".

Mr Trump referred to Mr Pompeo as having the same "thought process" as himself,t. Even US Ambassador to the United Nations Nikki Haley, who has been given a relatively free reign in her domain by Mr Trump and who has been more outspoken and media-friendly than the tacit Mr Tillerson, called the replacement a "great decision".

"Pompeo was the most political CIA director in memory," an administration official told Reuters, who spoke on the condition of anonymity.

Mr Pompeo is also on the same page regarding the Iran nuclear deal with the President.

In October, the president decided not to re-certify the historic deal, signed by Iran and six world powers - a signature foreign policy achievement by predecessor President Barack Obama. It opened the door for harsher economic sanctions to be placed on the country, the mitigation of which was a key inducement for Iran to comply with the deal. Tehran had pledged to rein in its nuclear program in return for some easing of those economic restrictions imposed on it by the US, the UN, and European Union.

European allies, and even Mr Tillerson according to some reports, continued to urge the President to extend the sanctions relief in order to save the deal. Mr Trump will not hear that from the hawkish Mr Pompeo.

“I look forward to rolling back this disastrous deal with the world’s largest state sponsor of terrorism,” he had tweeted in November 2016, when he was under consideration for the CIA post.

Between the two new faces, Mr Trump is not just adding sycophants, but people “who can actually help him make that outlook into reality,” Matthew Waxman, a Bush administration official who worked with Bolton during his years at the State Department, told the Lawfare blog of the Brookings Institution.