As a businessman and then a politician, Donald Trump has long held a hustler’s suspicion that friends are just as likely to rip you off as enemies – making them doubly duplicitous. This belief has led Trump, as president, to unrestrainedly attack longstanding American allies.

Australia, however, has proven the handy exception which allows Trump to deny the existence of a rule. He has loudly celebrated the US alliance with Australia, including hosting Scott Morrison at a rare state dinner. And the main features of the alliance – such as close military and intelligence ties – have been mostly unaffected by the change of presidency in January 2017, notwithstanding the two-year absence of a US ambassador in Canberra.

But even though Australia has not been the target of Trump’s wrath, it is increasingly clear that the country is being affected by the president’s approach to alliances. This is because Western nations and traditional partners of the United States are either defying it or seeking greater independence. As a result, the US’s global influence is diminishing – which, for Australia, decreases the value of the alliance.

A recent example of this shift was French president Emanuel Macron’s declaration that Europe should become less dependent for its security on a wayward US, and develop its own “European defence union”, rather than act collectively through NATO. Macron’s call for the creation of a European military was not entirely new, and France has a tradition of asserting diplomatic independence. But his comments, in an interview with The Economist, were unusually direct. “To have an American ally turning its back on us so quickly on strategic issues – nobody would have believed this possible,” he said. As Macron put it, Trump sees NATO as a “commercial project”. This approach has led NATO allies to increase their spending – but it is also prompting them to question the US’s commitment towards them.

In Asia, Trump’s attitude is having equally stark effects. The White House, for instance, has been largely unwilling and unable to help its two closest allies in the region – Japan and South Korea – mend a worrying rift over reparations from Japanese colonial rule of South Korea. Earlier this week, the United States Secretary of Defense, Mark Esper, visited South Korea and tried to persuade the country to stay in an intelligence-sharing agreement with Japan. South Korea has so far refused, and is due to leave the deal on Saturday.

During his visit, Esper also urged Seoul to pay more money to Washington for the 28,500 American troops there. South Korea lifted its contribution by 8 per cent last year, but Trump wants a fourfold increase. He is making similar demands of Japan, where the US has 54,000 troops. But these deployments are not mere “commercial projects”. They have helped to ensure that Asia has remained peaceful since World War II. Being the anchor of the region’s stability has given Washington improved status and influence, as well as economic benefits. Of the world’s ten largest buyers of US goods, five are in Asia.

But Trump’s push for allies in Asia to be more self-sustaining will, as in Europe, make them more defiant. Moreover, the current rhetoric from both Republicans and Democrats suggests that this transactional approach is likely to continue under future presidents, albeit without Trump’s belligerence.

At the moment, there are no signs in Canberra or Washington that the alliance is weakening, even under Trump. But as the US rethinks its global commitments, being its ally will no longer be as valuable as it once was, regardless of whether the prime minister and the president stand together and insist that their bond is unchanging.