Kyiv, Ukraine – No US president has known Ukraine better than Joe Biden.

While serving as Barack Obama’s vice president, he visited Kyiv six times – and joked that he had spent more time on the phone with then-Ukrainian President Petro Poroshenko than with his own wife Jill.

As president, Biden paid a surprise visit to Kyiv in February 2023, a year after Moscow began a full-scale invasion of Ukraine, to meet with Poroshenko’s successor Volodymyr Zelenskyy and pledge more military and financial aid.

And no US president has been so helpful in securing Ukraine’s very survival, Zelenskyy said hours after Biden dropped out of the presidential race on Sunday.

“We respect his difficult, but strong decision,” Zelenskyy wrote on X. “He supported our nation in the most dramatic moment in its history.”

Ukraine is grateful to President Biden for his unwavering support for Ukraine’s fight for freedom, which, along with strong bipartisan support in the United States, has been and continues to be critical.

Many strong decisions have been made in recent years and they will be…

— Volodymyr Zelenskyy / Володимир Зеленський (@ZelenskyyUa) July 21, 2024

Now, with Biden out of the race and former President Donald Trump the frontrunner to get re-elected in November, many in Ukraine are worried about the future of Washington’s military aid and political backing amid Russia’s slow but steady gains on the battlefield.

The keyword is “uncertainty”, said Kyiv-based analyst Volodymyr Fesenko.

“What’s obvious is that Trump will initiate talks [with Russia] about the war’s end, but the conditions of these talks are not clear,” he told Al Jazeera.

Vance view or Reaganite response?

Fesenko doesn’t think Trump would force Kyiv to recognise occupied areas in eastern and southern Ukraine as part of Russia because “it would mean the defeat of the United States, which is not acceptable for Trump”.

Most of the uncertainty has to do with the Ukraine policies among Republicans – and Trump’s own chameleonic decision-making.

Trump’s running mate JD Vance has said that he “doesn’t care about Ukraine one way or another” and wants Washington to stop aiding it altogether.

But the Republican Party’s wing, which calls itself “Reaganites” after former US President Ronald Reagan and often distances itself from Trump’s policies, is urging Washington to boost aid to Ukraine.

“Trump will most likely look for middle ground, for a balanced approach,” Fesenko said. “But his real position will only be understandable after the election.”

So far, Trump has only boasted that he’d use his art-of-the-deal skills to end the war promptly.

“I will have that war settled between Putin and Zelenskyy as president-elect before I take office as president on January 20,” he claimed during his June 27 televised debates with Biden.

He, however, never presented a detailed plan – nor has he named his future security team that would help mediate the conflict.

Zelenskyy talked to Trump on the phone last week – two days before Biden dropped out of the race – but very little is known about their conversation apart from superlatives from both sides.

A Zelenskyy aide told Politico that the call went “exceedingly well”, while Trump called it “very good”.

The phone call is a good start to a future relationship that is nothing but a “blank page” now, says German analyst Nikolay Mitrokhin of the University of Bremen.

Putin, with an army accused of committing regular war crimes in Ukraine, is a “better lobbyist” of Ukraine’s interests in the West than Zelenskyy himself, Mitrokhin said.

“Yet another portion of his atrocities may upturn all of Trump’s plans,” he told Al Jazeera.

So, under Trump Ukraine may lose financial support from the US, but get such arms as US armoured vehicles – something Biden was very reluctant to give away, Mitrokhin said.

Ukraine in the US election

More than half of Americans still firmly approve of aiding Kyiv, so how to deal with Ukraine and Russia’s war is a critical question for any future US president.

“The Ukrainian angle is of priority importance in this [presidential] race,” Lieutenant General Ihor Romanenko, Ukraine’s former deputy chief of General Staff of Armed Forces, told Al Jazeera.

Biden’s Vice President Kamala Harris, whom he endorsed to run in his stead, might want to boost aid to Ukraine to improve her own approval ratings.

In the only meeting between Harris and Zelenskyy on the sidelines of a peace summit in Switzerland in mid-June, the US vice president “reaffirmed” Washington’s support.

However, any decision in Washington to step up aid has to be “fast, energetic and involve a large share of modern weaponry”, Romanenko said.

“Only this can help the situation on the front line,” especially in Ukraine’s east, where Moscow has turned a blind eye to its harrowing losses of servicemen in recent months to seize several towns, he said.

Romanenko criticised Biden’s administration for being too slow and indecisive about the timing of arms supplies and the permission to use weaponry such as advanced missiles or F-16 fighter jets to deliver strikes deep inside Russia.

Troubled history

Years before Russia’s full-scale invasion, Ukraine was a political millstone for both Biden and Trump.

Back in 2016, when Kyiv was fighting pro-Russian separatists in the east, Biden pushed for the sacking of Ukraine’s allegedly corrupt Prosecutor General Viktor Shokin, threatening to freeze $1bn in US aid to Kyiv if he wasn’t removed.

Shokin claimed that Biden wanted to stop his investigation into Burisma, a Ukrainian natural gas producer that hired Biden’s son Hunter as a board member from 2014 to 2019.

“Biden was acting not like a US vice president, but as an individual interested in having me removed, having me gone so that I didn’t interfere in the Burisma investigation,” Shokin told this reporter in 2019.

The Republican Party echoed his allegations claiming that Hunter Biden had zero experience in energy management and had a heftily-paid sinecure to shield Burisma from scrutiny.

The Burisma probe nearly ended Trump’s presidency.

In 2019, he got impeached for the first time for freezing $400m in aid trying to force Zelenskyy to reopen the investigation.

Trump has shown more than once that he can hold a grudge, and has in the past been sympathetic towards Putin.

Unsurprisingly, some Ukrainians are horrified that if elected, Trump might throw their nation under the bus.

“He won’t hesitate for a second to turn the aid off and leave us all helpless,” Kateryna Kolesnik, a sales clerk in an electronics shop in central Kyiv whose brother Mykola fights in the east, told Al Jazeera.

Trump may forge an isolationist doctrine and keep the US active only when it comes to China and Israel, says Kyiv-based analyst Aleksey Kushch.

“This will create a new, more complicated reality for Ukraine,” he told Al Jazeera.

Meanwhile, some Ukrainian media outlets quote psychics who “foresee” Trump’s possible decisions.

“My visions and Tarot cards show that his politics will be unpredictable and will depend on his own interests,” a “molfar”, or clairvoyant named Max Gordeyev told the UNIAN news agency. “But the international community will remain on Ukraine’s side.”