Donald Trump emerged from his latest phone call with Chinese President Xi Jinping sounding less like the leader of a rival superpower, and more like an attentive understudy.

The US president hailed the conversation with China’s president for life, as “excellent” and expansive, while China’s leader used it to restate Beijing’s red lines - and to remind Washington who he believes should be setting the terms.

For Xi, Taiwan remains the “most important issue” in the relationship it was reported by the BBC. According to Chinese state media sources, Xi also told Trump to be “prudent” in supplying arms to the self-governing island. In the process he framing US weapons sales to Taipei as the primary source of any potential instability across the Taiwan Strait, making no mention of China’s daily naval and air patrols around Taiwan over the past year as part of a long-standing effort to intimidate the nation’s 24mn residents. Trump, by contrast, offered warm words about the relationship and his personal rapport with Xi, signalling little appetite for confrontation. No other US president has ever appeared so subservient to a Chinese leader.

The optics on this matter. Xi is not a benign global statesman seeing out his days, but a hardened regional strongman who has spent the past year tightening his grip at home, recently sidelining and purging two senior military generals once seen as potential counterweights against sudden and dangerous orders from within the Communist Party and the security establishment.

Those moves in the past week have only served to further concentrate power around Xi and sharpen his readiness to test rivals abroad, particularly in what he regards as China’s orbit - Taiwan included.

Yet Trump, the self-appointed leader of the free world, appears content to play along, almost cap in hand.

The soon to be 80-year-old American spoke enthusiastically about a planned visit to China in April and dangled the prospect of Beijing sharply increasing its purchases of US soybeans, an old Trumpian fixation, that again cast trade flows as a proxy for presumed regional harmony. The message was clear: keep the economic relationship sweet, and the geopolitics can at best wait – at worst for Taiwan - be ignored outright.

This posture comes as Western leaders once more queue up to re-engage Beijing, hoping to stabilise ties with the world’s second-largest economy. But where others have at least attempted to balance engagement with caution, Donald Trump’s tone when dealing with China now suggests deference. Repeatedly he has portrayed his relationship with Xi as not just functional but unusually good, a personal bond that he seems reluctant to jeopardise in any way.

Taiwan, inevitably, is the awkward complication, the elephant in the Oval Office when Trump’s direct line to Communist Party HQ rings. The US formally recognises Beijing rather than Taipei, but for decades it has underwritten the island’s day-to-day security through arms sales and political support. That balancing act has always been delicate, especially so under Democratic Party presidents in recent administrations . Under Trump, however, Taipei-Washington relations now look outright transactional.

Only weeks ago, The Trump administration signed off on an arms package for Taiwan worth roughly $11bn, including advanced missile systems and artillery, but not quite advanced enough to be considered top drawer arms by any stretch of the imagination. As is always the case, at the time, Beijing responded with its familiar and well-rehearsed fury, warning that US support for what it calls Taiwanese separatism would hasten a dangerous showdown.

Xi, it is understood, reiterated that line in his call with Trump, insisting that China must safeguard its sovereignty and territorial integrity – and in Xi’s eyes that means Taiwan.

What was missing though, was any sign that Trump pushed back.

Instead, he echoed Xi’s language of “mutual benefit(s)” and wanting to “work in the same direction”, even as the Chinese leader tightened his own partnership with Vladimir Putin and deepened coordination with Moscow hours earlier in a separate call.

For allies in Asia, Japan, South Korea and Taiwan especially, the concern is not just what was said, but what was implied. Xi is signalling resolve from a position of unprecedented personal control, while Trump is signalling flexibility - even a degree of eagerness - to accommodate.

The US president as a follower may flatter Xi’s sense of destiny, but it leaves Taiwan and the rest of east Asia exposed.