In an inaugural address on Monday, Trump said that his "proudest legacy will be that of a peacemaker and a unifier" and pointed to his support for a new ceasefire in Gaza.

Speaking to reporters as he returned to the White House after four years, Trump also suggested he would press Russia to make a deal to end its three-year invasion of Ukraine, quipping that President Vladimir Putin -- with whom he had famously warm relations in the past -- knows he is "destroying" his own country.

But in the throwback to the bedlam of his 2017-2021 term, Trump's return was also consumed by rage over grievances at home, and the most memorable foreign-policy line of his inaugural address was a vow to take back the Panama Canal, which the United States returned in 1999 but where Trump charges that China has gained too strong a foothold.

Trump has also spoken of seizing Greenland from NATO ally Denmark, moved to send the military to the Mexican border to stop migration, vowed tariffs even against close allies and announced the withdrawal of the United States from the World Health Organization and Paris climate accord, both home to almost every other country.

"Trump's worldview seems to be contradictory. He has a streak that is pro-peace and another streak which seems more confrontational and militarist," said Benjamin Friedman, policy director at Defense Priorities, which advocates restraint.

During his first stint in power, Trump ordered a strike that killed senior Iranian commander Qassem Soleimani and vowed confrontation with China, although he also boasted of keeping US troops out of new wars and sought diplomacy with North Korea.

"In the first term, the more confrontational and militarist streak won out more often than not" on tension spots such as Iran, Friedman said.

This time, he said, at least on Ukraine and the Middle East, Trump appears to have shifted to a more progressive stance.

But on Latin America, and in his selection of aides with hawkish views on China, Trump remains hawkish, Friedman said.

He said that Trump essentially had a 19th-century philosophy in line with populist president Andrew Jackson, feeling a comfort with threatening the use of force to achieve national interests.

Such a way of thinking, for Trump, "isn't consistent necessarily with being a peacemaker or a warmonger" but rather is a mix.

- Lesson from China? -

Trump made no clear mention of US allies on his inaugural day. In the past he has described NATO allies as freeloaders and pushed them to pay more for their own security.

However, Secretary of State Marco Rubio was meeting Tuesday with counterparts from Japan, India and Australia -- the so-called Quad of democracies which China sees as an effort to contain its rise.

Jon Alterman, a senior vice president at the Center for Strategic and International Studies, said that Trump should be mindful of lessons from China, whose assertive "Wolf Warrior" diplomacy brought together a number of Asian countries on the receiving end.

"It would be a profound shift if the United States went from being seen as the principal provider of security to being the principal source on uncertainty," Alterman said.

Trump, as he seeks to negotiate deals, "has an interest in keeping friendly countries on his side," Alterman said.

Kori Schake, who served in senior defense planning roles under former president George W. Bush, said it was too early to tell the impact of Trump's "chaos" on peacemaking and said that early actions could have been even more severe.

"But the actions he did take are still damaging. Withdrawing from the World Health Organization will give us less warning of emergent disease," she said.

"Antagonizing Panama is counterproductive and will fan anti-Americanism throughout the hemisphere," she said.