New Zealand can’t expect the United States to ride to its rescue in a military conflict if it fails to spend “a reasonable amount” on its defence, a retired American general and former Trump administration official says.

Former brigadier general David Stilwell has also expressed scepticism about the odds of a lasting trade deal between the US and China, saying the Asian superpower has shown it cannot be trusted to keep its word.

US President Donald Trump travelled to Beijing last month for a summit with Chinese leader Xi Jinping, in part to deal with a long-running trade war between the two countries.

Stilwell, who followed up a 35-year career in the US Air Force by serving as Assistant Secretary of State for the Bureau of East Asian and Pacific Affairs during Trump’s first term, said there was no point in negotiating a deal with China given it had “repeatedly instantly violated” previous pacts.

“I don’t understand the point of even going to China and talking to them, unless it’s going to be a mailed fist [the threat of superior force] and quiet threats to let them know we’re serious,” he told Newsroom during a visit to New Zealand.

The only way for the US to convince China it was serious was to show a willingness to walk away from substandard deals and say no, he said, arguing the Chinese government’s talk of “win-win cooperation” was not based in reality.

“The Chinese phrase for it is, ‘I live, you die’, and it comes from a culture of a long history of famine and want due to climate issues…

The best way to get things done and achieve your national objectives … is to dictate terms – peace through strength. You have to show strength, you have to call them on every time they violate an agreement, you have to be very careful about what agreements you enter into, and I know it’s a very stark view of the world.”

Stilwell said the main threat posed by China to Taiwan was not a military invasion but information and economic warfare, with similar risks for the rest of the world.

The best response was to demonstrate a strong relationship with regional partners like Australia, Japan and Philippines that shared similar concerns.

“We are all in the same boat, reacting to PRC aggression, so they can take you out one by one individually but they cannot deal with a group.”

Stilwell, who is due to speak about the state of the rules-based order at the annual Otago Foreign Policy School – hosted by the University of Otago – said he had long been sceptical about the benefits of the rules-based order, dating back to a 2011 visit to Europe while still in the military.

“We start off by saying, ‘Hey, how are things going? What are you concerned about here in Oslo, or wherever,’ and they’re wringing our hands, going, ‘We are so worried about Russians and Putin’…

“Of course, our obvious follow-up question was, ‘So how are you doing on your 2 percent mandatory entry-level investment in defence to deter aggression by the Russians?’ And they’re like, ‘Oh well, you know, we’ve got social programmes, free health care, free college, and all the rest, so we couldn’t possibly pay one more dime to deter Russia’…

“That’s what began my kind of hard thinking about what does a rules-based international order mean when there’s no power or leverage to force those who would not live up to the expectations to do the right thing.”

New Zealand’s own defence spending has come under the microscope in recent months. At Singapore’s Shangri-La Dialogue, US War Secretary Pete Hegseth suggested the country was “freeloading” with its failure to meet a 3.5 percent defence spending target for American allies.

Asked about those remarks, Stilwell said: “There’s no contract that says you’re going to commit 2 percent or 3 percent or 5 percent – there’s nothing that you have agreed with the United States that says you’re going to spend to some level.”

But a country that didn’t want to spend “a reasonable amount” on its security couldn’t expect other nations to come to its rescue in the event of a conflict, he added, naming Japan as an exemplar for other world leaders to follow. Prime Minister Sanae Takaichi ramping up the country’s defence spending and pushing for constitutional revisions that would undo its pacifist stance formed after World War II.

“Rather than complain about the US, look at what Japan’s doing in an era where increasing Chinese aggression … should be a wake-up call, and New Zealand has certainly heard that wake-up call and is doing the right thing in that regard.

“If you expect the US to help – and we are more than willing, because what affects you affects us all, terms of trade, movement, mobility, whatever – you can’t expect us to care more than you do.”