The two candidates for US president offer starkly different visions of the world, with November's election carrying the potential to dramatically change policy toward Ukraine and other partners.
Vice President Kamala Harris largely offers continuity with President Joe Biden, though she has sought more nuance on the Middle East in particular, while a return of Donald Trump would likely mean a sharp rupture from current US foreign policy.
Few issues divide the two candidates as much as Ukraine. Trump has scoffed at the billions of dollars in US aid to Ukraine, saying that Russia, which invaded its smaller neighbour in February 2022, is destined to win.
The Republican has in the past has voiced admiration for Russian strongman Vladimir Putin, comments seized upon by Harris, who in their September debate said, "If Donald Trump were president, Putin would be sitting in Kyiv right now."
Harris has promised to keep up support for Ukraine, while Trump's aides have suggested leveraging US assistance to force Ukraine into territorial concessions to end the war quickly.
Trump has also mocked Ukrainian President Volodymyr Zelensky as the "greatest salesman" in a jab at his lobbying for US military aid, although the two recently had a cordial meeting.
Harris and Trump are both solidly pro-Israel but they diverge on how far to pressure the US ally as war spreads in the Middle East.
Harris, like Biden, has made clear she will keep arming Israel, distancing herself from calls from the left of their Democratic Party for an arms embargo for the sake of sparing civilians.
But Harris has also called for Palestinian "self-determination" and said she will "not be silent" on the suffering in the Gaza Strip.
Trump's Republican base is staunchly pro-Israel and he has repeatedly attacked Biden's record as a failure, including on Tuesday as Iran fired missiles in response to Israel's killings of top Hizbollah leaders and Iranian commanders in Lebanon.
Trump as president took a series of landmark actions on Israel's behalf, including moving the US embassy to flash point Jerusalem and giving Arab nations incentives to recognise Israel.
But he also has a complicated history with Israeli Prime Minister Benjamin Netanyahu, whom he criticized for joining other world leaders in recognising that Biden won the 2020 US election -- an outcome that Trump refused to accept despite overwhelming evidence.
Policymakers of both US political parties have spoken of China as the top long-term challenger, though they differ on rhetoric and approach.
Trump has relentlessly attacked China in his stump speeches and has vowed to impose massive tariffs on Chinese goods, hoping to boost manufacturing at home. But despite his public statements, he has also indicated he is open to deal-making with President Xi Jinping.
Biden has in some ways gone further than Trump, including by imposing a sweeping ban on high-tech chip exports.
Harris has highlighted Trump's reluctance while he was in office to take similar measures, charging that he "basically sold us out," with China's military benefiting from US technology.
Meanwhile in Taiwan, the self-ruling democracy claimed by Beijing, Trump has caused jitters by suggesting that it pay for its defence, likening the United States to an insurance company.
Harris, as vice president, has pledged to maintain the status quo, stating that "we support Taiwan's self-defence, consistent with our longstanding policy."
In a sharp break from previous presidents of both parties, Trump has questioned the utility of NATO, the collective defence alliance formed at the start of the Cold War.
Trump even said in February he would encourage the Russians to do "whatever the hell they want" to NATO allies that do not pay more on defence.
Harris has frequently pointed to Trump's remarks as she promises, like Biden, to work with allies and stand by NATO.
Trump in his first term showed he was ready to break with international agreements he does not like, including the Iran nuclear deal.
He would also be expected to champion tough US pressure against leftist leaders in Latin America, particularly Cuba and Venezuela, although neither Biden nor Harris has deviated sharply from his approach.
* The writer is from AFP