One of the president’s biggest economic campaign promises was a new, muscular approach to trade featuring hefty tariffs on China and other rivals as well as a wholesale ripping-up of US trade agreements. Things could still change. Yet, nine months in, it is fair to say Mr Trump is looking increasingly like a bully without a playground in which to exercise his muscle.

He may bark to aides gathered in the Oval Office that he wants tariffs, and threaten on Twitter to pull out of trade agreements. But the ranks of people in his administration eager or willing to carry out those threats are dwindling. Altogether, the threats themselves are looking increasingly hollow. There are three big reasons for that.

1. Trump doesn’t control the system

The US presidency comes with a lot of power attached. But the reality is also that its influence over trade is limited, both by the US constitution and existing laws. Mr Trump may want to impose tariffs unilaterally, yet he has very little power to do so on a whim. The US constitution gives the power to regulate trade and impose tariffs to Congress. And even those statutes that give the president the most latitude to act require a process and justification at the very least.

Just look at what has happened with the president’s stalled plans to impose tariffs on steel imports on the grounds of US national security. Administration officials insist they are still working on a plan. But what is holding up the steel project — which involved using a 1974 trade law that on the face of it gives the president great powers — is in part the laborious study involved and the inter-agency consultations required.

Then there is Congress. The Republicans who control the legislature are by and large more pro-trade than the president. They are also more adept at using their power over the system.

Moreover, the steel exercise illustrates two other parts of the system that Mr Trump doesn’t control: US business and economic reality. After a shy start, everyone bar the steel sector in the US business community has grown increasingly vocal about its distaste for anything that raises the price of steel. They have also been building a compelling case for how it would hurt the US economy.

2. The US doesn’t wield the power Trump thinks it does on trade

The best example of this is the (again) stalled debate within the administration over pulling the US out of a South Korea-US trade agreement (Korus) that came into force in 2012. Jonathan Swan of Axios did a nice job at the weekend of detailing the conversation within the administration in recent weeks and how (as was the case with Nafta in April) the president got very close to issuing a formal notice of withdrawal.

The idea has since stalled, thanks to North Korea’s recent nuclear test and the acceptance (for now) by the president that withdrawing from a trade agreement with South Korea in its wake does not make geopolitical sense.

But the example also illustrates how the US has been misplaying its cards.

During a special meeting convened during the summer to discuss Mr Trump’s concerns over Korus and the US trade deficit with South Korea, Robert Lighthizer, the US trade representative, issued a list of unilateral concessions that he wanted to see Seoul make. Those, according to people briefed on the discussions, included accelerating the Korus schedule for South Korea’s gradual removal of certain tariffs on US goods and a freeze on the same applying to Korean imports into the US.

Mr Lighthizer was in effect using the same threat-laced playbook that he employed in the 1980s while negotiating “voluntary export restraints” with Japan as a senior trade official in the Reagan administration. But the answer this time from South Korea’s trade minister, Kim Hyun-chong, was a resounding “no thanks”.

The response by Mr Kim, who led the Korean team that negotiated the original deal, was very well calculated. He was aware of one blunt reality: the unwinding of Korus would lead to much higher tariffs on US imports into South Korea than vice versa.

But there was another. Simply, the US in the Trump era does not speak with a unified voice on trade. Congress, the US Chamber of Commerce, myriad agricultural groups and the nation’s chief executives have all come out against the Trump plan to withdraw from Korus during the past week. And that illustrates Washington’s diminishing power at the negotiating table.

3. Business is no longer afraid of Trump

The defining debate so far on trade within the Trump administration has been between the “economic nationalists” and the globalists. However, with one high-profile exception (Mr Trump’s withdrawal on day three of his presidency from the Trans-Pacific Partnership), the globalists have been winning the war.