With his insults of US allies, soft spot for autocratic rulers and contempt for international agreements, President Donald Trump has turned US foreign policy on its head over a chaotic four years.
But behind the bombast, is there in fact a "Trump Doctrine," a method behind the madness on which voters will decide on November 3?
Trump has embraced the term "America First," reflecting his campaign promises four years ago of curbing immigration, confronting a rising China, winding down "endless wars" and renegotiating trade deals that the tycoon charged had hurt US workers.
Colin Dueck, a visiting scholar at the American Enterprise Institute and author of "Age of Iron: On Conservative Nationalism," said that Trump's worldview has on some core issues been strikingly consistent.
"I think there is a kind of Trump Doctrine, even though it obviously doesn't fit the usual DC pattern at all," Dueck said.
Dueck noted that Trump has constantly prioritized US commercial interests and, when not appearing alongside the security establishment, has questioned the need for military deployments, most recently vowing to speed up the US withdrawal from Afghanistan.
In style, the real estate mogul -- who has boasted for decades of his negotiating skills -- has shown a willingness to engage widely, putting out not just barbed tweets but also eyebrow-raising praise.
The rhetorical whiplash has been no more stunning than on North Korean leader Kim Jong Un, with whom Trump said he "fell in love" a year after he mocked him as "Little Rocket Man."
"He's open to negotiating with almost anybody other than ISIS," Dueck said of Trump. "The up-and-down ladder of escalation is characteristic."
Even if Trump is not known to be a student of history, Dueck said that Trump was reviving a pre-Cold War US approach to the world.
Leaders of Trump's Republican Party a century ago similarly ran on the "America First" slogan -- slamming the brakes on immigration, rejecting the fledgling League of Nations and vigorously promoting economic goals.
"The US as an independent actor, not thinking of multilateral commitments of having primary importance, and just looking at the world from the point of view of does this serve American interests narrowly defined -- it was a dominant strain of American foreign policy for generations prior to World War II."
- Trump achievements? -
Trump, who is trailing in polls to Democrat Joe Biden, is highlighting several international wins in recent months after disappointments earlier in his term.
In September, the United Arab Emirates and Bahrain agreed to recognize Israel, a coup for the Jewish state -- a major cause for the Republicans' evangelical Christian base -- as Gulf Arabs and Israel both rally behind Trump's campaign against Iran.
Afghanistan's government and the Taliban have opened peace talks, although there has been no visible progress, and the administration has found limited but growing success in coaxing nations to reject China when adopting fifth-generation internet.
But relations have hit rock-bottom with European allies, which resent Trump's coarse approach and his rejection of international diplomacy -- including of the Paris climate accord at a time when temperatures are rising dangerously.
Iran has stepped up nuclear work and flexed muscle around the region even as its economy is devastated by US sanctions unilaterally imposed by Trump.
A Pew survey found that views of the United States in other wealthy nations had plunged to historic lows over doubts on Trump's leadership, especially over the Covid-19 pandemic.
Thomas Wright, a senior fellow at the Brookings Institution, said that Trump had few real achievements and that his foreign policy was largely "flirting with catastrophe."
Gulf Arabs had already been warming to Israel for a decade, while the tougher approach on China is part of a bipartisan consensus in Washington, Wright said.
- Impact beyond election -
On the flip side, Trump has for the first time raised questions about US commitments to the NATO alliance and aggravated the impact of the Covid crisis, Wright said.
"I think there's uncertainty about America's role in the world that wasn't there before," Wright said.
"With a combination of Trump and Covid, we don't really know if we're ever going to go back to sort of a more open global economy," he said.
Even if Trump loses, his impact will likely be long-lasting for the United States and the world.
He has shattered a Republican consensus, barely questioned in his party during George W. Bush's presidency, of supporting robust military action, unfettered free trade, at least modest immigration and democratic values abroad.
"Trump couldn't have won on his own," Dueck said. "He needed millions of people to nod their heads and say, actually, yeah, why are we continuing to operate on autopilot?"