Donald Trump has picked JD Vance - a staunch opponent of aid for Ukraine who wants the US to refocus on Asia - as his running mate, signalling a potential shift away from Europe if the Republican candidate wins in November.
Mr Vance - a 39-year-old retired US Marine and best-selling author - is ideologically close to the former president, and his views on foreign policy could help shape Mr Trump's second term in office if he defeats Democrat Joe Biden.
"I gotta be honest with you, I don't really care what happens to Ukraine one way or another as a country," the senator from Ohio said on a podcast in April.
Mr Vance was one of the fiercest opponents of the approval of $61 billion (€55.9m) in new military aid for Ukraine, which was stalled by Republican politicians for months earlier this year - a time in which Russia made battlefield gains.
The United States has provided tens of billions of dollars in military assistance for Kyiv since Russia launched its full-scale invasion of Ukraine in February 2022.
But Mr Vance and other Trump allies in Congress argue that the US cannot continue to fund the war indefinitely, and a Trump victory in November would throw future American assistance for Ukraine into doubt.
Mr Trump has said he would quickly end the conflict, raising the spectre that Ukraine could be pushed to negotiate with Russia from an unfavourable position.
Ukrainian President Volodymyr Zelensky said that he was not concerned about the prospect of another Trump presidency, despite indications his administration could be more sympathetic to the Kremlin.
'Subsidising European security'
"I think that if Donald Trump becomes president, we will work together. I'm not worried about this," Mr Zelensky told a news conference.
Asked about the consequences of a Trump presidency for Ukraine, US State Department spokesman Matthew Miller said both politicians and the American public back continued support for Ukraine.
"The American people strongly support continued assistance to Ukraine. They strongly support allowing Ukraine and helping Ukraine to defend itself against Russia's aggression. It's not just the American public, but it's bipartisan majorities in both houses of Congress," Mr Miller told journalists.
For Mr Vance, European countries have relied on the US for security for far too long, and he advocates a shift to increasingly concentrate on east Asia.
"NATO countries can't be welfare clients of the US," he told Fox News in June, while he said in February that "we have been subsidising European security to the tune of trillions of dollars".
Speaking at the Munich Security Conference earlier this year, Mr Vance argued that "the United States has to focus more on east Asia. That is going to be the future of American foreign policy for the next 40 years, and Europe has to wake up to that fact.
"The point is not we want to abandon Europe. The point is we need to focus as a country on east Asia, and we need our European allies to step up in Europe," he said, urging the continent to "take a more aggressive role in its own security".
