Now, a year after clinching the presidency on that ambitious platform, Trump is leapfrogging between the Asian countries he once decried as top culprits of that trade imbalance in what could be his best opportunity yet to confront the region's leaders. But while trade is still a top item on the agenda -- certainly for Trump -- the President also has to train his focus on the urgent threat of North Korea.
The question now is whether he will strike a balance or press forward with his aggressive negotiation style that could ding key partnerships.
The specter of his potentially risky gambit hangs heaviest as Trump arrives here in the South Korean capital Tuesday. Trump has repeatedly lambasted the US-South Korean free trade agreement, known as KORUS, and threatened to withdraw from the pact altogether.
'Not the time for trade-offs'
Delivering such a threat while he is in South Korea could widen the divide between Seoul and Washington at a time when the former is already uneasy with Trump's approach and as the strength of the alliance will be a key barometer of the success of the US-led pressure campaign on North Korea.
"This not the time for trade-offs," said Bill Richardson, the former US energy secretary, UN ambassador and envoy to North Korea. "The North Korean threat is too serious. This is a time to come together in confronting and dealing with North Korea."
That concern is echoed throughout the US and South Korean foreign policy establishments. But for now, Trump is showing no signs that he's prepared to abandon his decades-old focus on the trade imbalance between the US and certain countries.
Speaking Monday in Tokyo, the first stop of his five-nation Asian tour, Trump knocked the US-Japan trading relationship as unbalanced.
"The United States has suffered massive trade deficits with Japan for over 70 years," Trump told a gathering of top American and Japanese business leaders. "We want fair and open trade, but right now our trade with Japan is not fair and it's not open ... Right now, our trade with Japan is not free and it's not reciprocal."
But while Trump and Japanese Prime Minister Shinzo Abe enjoy one of the closest relationships in the region and are already in lockstep on how to approach the North Korean threat, Trump has a much less cohesive relationship with South Korean Prime Minister Moon Jae-in. Beyond his criticism of KORUS as a "horrible" deal, Trump has also pressed a much more aggressive stance on North Korea, while Moon was swept into office on a platform of increasing dialogue with Pyongyang.
South Korea has already been pushed into a tough corner since accepting the installation of a sophisticated US anti-missile system known as THAAD on its territory, bowing to pressure from Washington despite considerable political opposition within South Korea and from China, which took retaliatory economic action that has cost South Korea billions of dollars in lost revenue.
"This is the wrong time to be picking a fight with our allies," said Sue Mi Terry, a former CIA analyst and senior National Security Council official under President George W. Bush. "South Koreans are already highly anxious."
The US-South Korea alliance has endured, but experts are warning that Trump's outsized focus on KORUS -- particularly with his emphasis on withdrawal and sweeping changes -- could weaken the partnership between the two countries, which would play into North Korea's hands, Terry said.
A strengthened -- rather than diminished -- US-South Korea relationship would also reinforce Trump's hand as he skips from Seoul to Beijing, where Chinese officials have sought to counter the US' aggressive pressure campaign with calls for dialogue with North Korea.
"If we want the Chinese to be helping us on North Korea, we need to demonstrate that our alliances are becoming stronger," said Michael Green, the former senior director for Asian Affairs at the National Security Council in George W. Bush's White House.
In Beijing, too, Trump will be forced to balance his aggressive trade agenda and his efforts to win support for his North Korea strategy.
Past US administrations have made clear to China that the two issues would remain fundamentally disentangled. But after a campaign that vilified China and called for double-digit tariffs on Chinese imports, Trump has floated the idea of conceding to China on trade grounds if it steps up pressure on the North Korean regime.
Despite Trump's comments, a senior White House official insisted Sunday in a briefing with reporters that they do not "anticipate trade offs."
"The United States isn't going to barter away our interests on the trade front in order to make gains doing what the entire world has more or less obligated itself to do: And that is to contain and confront the threat from North Korea," the official said.
Still, even as Trump prepares to arrive in Beijing with the goal of making good on his campaign promises to counter predatory Chinese trade practices and rebalance the trading relationship, Trump has now changed expectations in Beijing. And Chinese President Xi Jinping may look to extract trade concessions in exchange for additional support on pressuring North Korea.
The high-wire act that will be expected of Trump during his 13-day swing through Asia will not be a new one for Trump, who has had to balance his desire for aggressive trade action to boost US manufacturing and reduce the US' trade deficit with the increasingly urgent threat of North Korean advances in its nuclear and ballistic missile capabilities.
Trump has continued to float drastic measures to rebalance the US-South Korea trading relationship, ordering his aides in September to prepare for withdrawal from the treaty. But he has since backed off that threat and the US Trade Representative Robert Lighthizer, who will be at Trump's side through his Asian swing, has said the US was looking for "some changes" to the deal rather than preparing for a rash withdrawal.
And while Trump has queued up several trade investigations that could allow him to impose tough tariffs aimed at key imports from China and other countries, Trump has so far held off on some of the toughest measures that have come across his desk since coming into office.
He softened his aggressive rhetoric on Chinese trade abuses since coming into office in favor of wooing the Asian powerhouse into tough action against the North Korean regime. And he delayed plans to investigate China over intellectual property violations in August in order to secure China' support for a fresh round of UN Security Council sanctions.
"He's adopted a much more practical trade strategy compared to what he was saying as candidate," said Michael O'Hanlon, a senior fellow at the Brookings Institution.
But, O'Hanlon added, "we don't really know where it's headed."