While campaigning to regain the U.S. presidency, Donald Trump said that he would be able to end Russia's war in Ukraine in 24 hours, warned that Israel would be "eradicated" if he lost the election and vowed sweeping new tariffs on Chinese imports.

Now that Trump has claimed victory, many at home and abroad are asking an urgent question: will he make good on his long list of foreign policy threats, promises and pronouncements?

The Republican has offered few foreign policy specifics, but supporters say the force of his personality and his “peace through strength” approach will help bend foreign leaders to his will and calm what Republicans describe as a "world on fire".

They blame the global crises on weakness shown by President Joe Biden, though his fellow Democrats reject that accusation.

America’s friends and foes alike remain wary as they await Trump’s return to office in January, wondering whether his second term will be filled with the kind of turbulence and unpredictability that characterized his first four years.

Trump’s 2017-2021 presidency was often defined on the world stage by his "America First" protectionist trade policy and isolationist rhetoric, including threats to withdraw from NATO.

At the same time, he sought to parlay his self-styled image as a deal-making businessman by holding summits with North Korea, which ultimately failed to halt its nuclear weapons program, and brokering normalization talks between Israel and several Arab neighbors, which achieved a measure of success.

"Donald Trump remains erratic and inconsistent when it comes to foreign policy," analysts for the European Council on Foreign Relations wrote in a blog post during the U.S. campaign.

"Europeans are still licking their wounds from Trump’s first term: they have not forgotten the former president’s tariffs, his deep antagonism towards the European Union and Germany," they said.

Trump and his loyalists dismiss such criticism, insisting that other countries have long taken advantage of the U.S. and that he would put a stop to it.

Ending the Ukraine war

How Trump responds to Russia’s war in Ukraine could set the tone for his agenda and signal how he will deal with NATO and key U.S. allies, after Biden worked to rebuild key relationships that frayed under his predecessor.

Ukrainian President Volodymyr Zelenskiy congratulated Trump on social network X, describing Trump's peace-through-strength approach as a "principle that can practically bring just peace in Ukraine closer".

Trump insisted last year that Russian President Vladimir Putin never would have invaded Ukraine in 2022 if he had been in the White House, adding that “even now I could solve that in 24 hours”. But he has not said how he would do so.

He has been critical of Biden's support for Ukraine and said that under his presidency the U.S. would fundamentally rethink NATO's purpose. He told Reuters last year that Ukraine may have to cede territory to reach a peace agreement, something the Ukrainians reject and Biden has never suggested.

NATO, which backs Ukraine, is also under threat.

Trump, who has railed for years against NATO members that failed to meet agreed military spending targets, warned during the campaign that he would not only refuse to defend nations "delinquent" on funding but would encourage Russia “to do whatever the hell they want” to them.

"NATO would face the most serious existential threat since its founding," said Brett Bruen, a former foreign policy adviser in the Obama administration.

A freer hand for Israel?

Trump will also confront a volatile Middle East that threatens to descend into a broader regional conflict. Israel is fighting wars in Gaza and Lebanon while facing off against arch-foe Iran, even as Yemen’s Houthis fire on commercial shipping in the Red Sea.

He has expressed support for Israel’s fight to destroy Hamas in the Palestinian enclave but has said Prime Minister Benjamin Netanyahu, a Trump ally widely believed to have favored his return to power, must finish the job quickly.

Trump is expected to continue arming Israel, whose existence he said would have been endangered if Harris had been elected - a claim dismissed by the Biden administration given its staunch support for Israel.

His policy toward Israel likely will have no strings attached for humanitarian concerns, in contrast to pressure that Biden applied in a limited way. Trump may give Netanyahu a freer hand with Iran.

But Trump could face a new crisis if Iran, which has stepped up nuclear activities since he abandoned a nuclear deal with Tehran in 2018, rushes to develop a nuclear weapon.

When Trump was last in the White House, he presided over the signing of the Abraham Accords between Israel, the United Arab Emirates and Bahrain. But those diplomatic deals did nothing to advance Palestinian statehood in the West Bank and Gaza.

Still, Trump is likely to push for historic normalization of relations between Israel and Saudi Arabia, an effort initiated during his first term and which Biden has also pursued.

Mixed messages on China

Trump made a tough stance toward China central to his campaign, suggesting he would ramp up tariffs on Chinese goods as part of a broader effort that could also hit products from the EU. Many economists say such moves would lead to higher prices for U.S. consumers and sow global financial instability.

He has threatened to go further than his first term when he implemented a sometimes chaotic approach to China that plunged the world's two biggest economies into a trade war.

But just as before, Trump has presented a mixed message, describing Chinese President Xi Jinping as “brilliant" for ruling with an “iron fist”.

Trump has also insisted that Taiwan should pay the U.S. for defense. But he has said China would never dare to invade democratically governed Taiwan, which Beijing claims as its territory, if he were president.

Another unknown is how Trump will craft his national security team, though many critics believe he will avoid bringing in mainstream Republicans who sometimes acted as "guardrails" in his first term.

Many former top aides, including ex-national security adviser John Bolton and his first chief of staff John Kelly, broke with him before the election, calling him unfit for office.

Trump has been quiet about whom he might appoint but sources with knowledge of the matter say Robert O'Brien, his final national security adviser, is likely to play a significant role.

Trump is expected to install loyalists in key positions in the Pentagon, State Department and CIA whose primary allegiance would be to him, current and former aides and diplomats told Reuters.

The result, they say, would enable Trump to make sweeping changes to policy as well as to federal institutions that implement - and sometimes constrain - presidential actions abroad.