IT was in a recent speech in Washington that Antony Blinken, US secretary of state, said that a “hinge moment in history” has been reached.

“What we are ­experiencing is more than a test of the post-Cold War order. It’s the end of it,” Blinken told students at the Johns ­Hopkins School of Advanced ­International ­Studies.

He went on to describe how in his view “decades of relative geopolitical ­stability have given way to an ­intensifying competition with authoritarian, revisionist powers”, challenging the ­principles enshrined in the UN charter – among them, sovereignty, territorial ­integrity and independence.

As for the frontline in this global ­struggle, nowhere was this more “­immediate and acute” than in Russia’s war of aggression in Ukraine, Blinken added.

These are strong words – the kind that would suggest that when faced with such challenges as those in Ukraine, the ­United States and other allies will continue to do all they can to support Kyiv.

That much US president Joe Biden (below) was at pains to reiterate last Thursday when at the White House he told ­Ukrainian ­leader Volodymyr Zelenskyy that he would ­“ensure the world stands with you,” against Russia’s invasion.

On the face of it, the Biden ­administration certainly appears to be backing up those words with deeds. No sooner had Zelenskyy emerged in New York at the UN General Assembly where he had a showdown with the invader of his country than he was then in ­Washington lobbying for further support.

The National: President Joe Biden walks from the podium after the State of the Union address

Biden in turn responded by ­announcing an additional $325 million in military aid that included air defence capabilities, cluster munitions and anti-tank weapons. He said, too, that the US will also begin ­delivering M1A1 Abrams main battle tanks to Ukraine in the coming days.

Most significant of all, he told ­Zelenskyy that the US was willing to provide ­advanced long-range, surface-to-surface missiles from the US Army Tactical ­Missile System, or ATACMS. Ukraine has long sought such weapons which could blast Russian supply lines, logistics depots and headquarters far behind the front lines. They will be supplied, however, only with assurances from Kyiv they won’t be used to strike Russian territory for fear of escalation.

All good news, you might think, for Zelenskyy at precisely the moment when his country’s armed forces are locked in bloody combat as part of an offensive that many still believe has the capacity to shift the war in Kyiv’s favour.

But as unwavering as such pledges from Ukraine’s allies sound, they depend on two uncertain variables. One is the West’s ability to furnish Ukraine’s army with enough weapons and ammunition. The other is the political will to keep handing them over.

As conventional wisdom has it, wars end either by outright military victory or by negotiations. But more often than not, as history has shown in America’s war in Vietnam or France’s war in Algeria, wars can end because of dwindling public ­support or a shift in the domestic ­political landscape. Already some diplomatic ­analysts are pointing to signs of what they have dubbed “Ukraine fatigue” among some of the countries that have ­previously pledged unending support.

Enter Ukraine’s neighbour Poland which has been one of Kyiv’s ­staunchest supporters. Ever since the Russian ­invasion 19 months ago, Warsaw has ­provided military and economic aid, championed Ukraine’s position on ­international forums, taken in millions of refugees and allowed its territory to ­become the main conduit for ­Westerns arms shipments heading for the ­frontlines.

But Poland next month on October 15 votes in a general election in which the ruling Law and Justice (PiS) party is in the fight of its political life and, in a ­scramble for votes, is taking aim at the country’s alliance with Ukraine.

Last week, Polish prime minister ­Mateusz Morawiecki announced a halt to weapons exports to Ukraine amid a pre-election row over grain exports. Morawiecki and his governing party ­appear to be engaged in a push to ­reassure voters that it will not put Ukraine’s ­interests ahead of Polish ­citizens, and ­especially farmers, who are angry over low prices for their produce that they blame on an influx of cheap ­Ukrainian grain.

“Ukraine realises that in the last months, they’re not bordering Poland, they’re bordering Polish elections,” was how Ivan Krastev, chair of the Centre for Liberal Strategies in Sofia, Bulgaria summed up the current mood in an ­interview with Politico magazine.

So for now, “the votes of a hundred thousand Polish farmers are more ­important for the government than what is going to be the cost for Ukraine. And we’re going to see this happening in many places”, Krastev added.

One of those other places is ­Slovakia where forthcoming elections next week on September 30 also risk ­weakening the West’s support for Ukraine as ­Russia-friendly parties are expected to make a comeback in the Central ­ European ­country.

Leading in the polls is Smer, the party of former prime minister Robert Fico, who resigned in 2018 following anti-corruption protests. Smer has been tipped to win 20% of the vote but would require several coalition partners to govern.

Fico has already surpassed ­Viktor ­Orban – the “alt-right” leader in ­neighbouring Hungary – in his pro-Russian positioning and has repeatedly stressed that if he returns to power, his first ­action will be to stop sending Kyiv weapons and support.

That said, some analysts have downplayed the importance of Poland and ­Slovakia’s role at the moment, pointing out that there aren’t many weapons left to deliver in the countries’ armouries.

But that doesn’t stop others from ­feeling uneasy. According to Dominika Hajdu, a senior analyst at Slovak think-tank Globsec, next week’s vote stands out as “one of the very few elections where helping Ukraine is part of the campaign and where the leading party is against this help”.

Speaking to the Financial Times ­recently, Hajdu described the ballot as “an election that can strongly influence the unity of the EU and Nato in terms of support for Ukraine”.

It’s precisely for this reason that the result of Slovakia’s election – a ­country that until now like Poland was fully ­supportive of Kyiv – matters hugely in terms of the war’s outcome.

But are these positions being adopted by Poland and Slovakia simply political grandstanding, or real proof that Nato and Europe’s unwavering support for Ukraine is no longer so unwavering? While it would be easy to write off the tensions as only electoral friction, some maintain there are reasons to believe they could persist beyond the campaigns.

As one Western diplomat who spoke to Politico magazine on condition of ­anonymity pointed out, the grain dispute between Warsaw and Kyiv reveals deeper misgivings about Ukraine joining the EU.

“For 18 months, Poland has badgered any member state that would utter the slightest hesitation towards Ukraine,” the diplomat said. “Now they’re showing their true colours,” the official insisted.

To date the unity of European ­public opinion appears to have surprised ­Russian president Vladimir Putin. But Moscow is doubtless watching closely in the hope that the political landscape and public opinion among Ukraine’s allies is turning in his favour, leaving Kyiv high and dry.

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BUT even as the shift in Poland and Slovakia’s positioning is hugely significant, Moscow knows that the biggest danger to unity among Ukraine’s allies would come from a change in Washington. As Mark Leonard, co-founder and director of the European Council on Foreign Relations (ECFR), pointed out in an article earlier this year, “Biden has been almost as important to building European unity from a positive direction as Putin has been from a negative one”.

“If Donald Trump – or another ­America First Republican – returns to the White House in 2024, US support for Ukraine and unity with Europe will look much less certain. Any change in American politics would leave European unity particularly vulnerable,” says Leonard, with his view shared by many observers.

According to the Washington Post, since Russia’s invasion began in ­February 2022, the US has ­committed $113 billion to ­military, economic and ­humanitarian aid for Ukraine and other countries ­impacted by the war. With the Biden ­administration set to ask ­Congress to ­approve an ­additional $24bn and ­Congress already in turmoil amid a ­looming shutdown of the federal ­government, aid for Ukraine is likely to be considered separately, at least in the House of Representatives.

In other words, this means it can no longer expect a free ride on a separate piece of must-pass legislation. Early in the war the American public showed ­immense support for Ukraine – and ­politicians acknowledged that. The Ukraine ­Democracy Defence Lend-Lease Act of 2022, designed to speed up the transfer of weapons to Ukrainian forces, passed the House in April last year with support from 196 Republicans (166 of whom remain in Congress). Only 10 ­opposed the measure.

But the views of the American public, ­according to some polls, are changing and so too is the position of some US ­politicians – notably Republicans. Those critical of Biden’s policy and eyeing next year’s US presidential elections were quick to seize on a recent CNN poll ­indicating that 55% of Americans ­oppose more funding for Ukraine on top of the $43bn in US security assistance ­already provided.

America’s big budget deficit and high interest rates make politicians of all ­parties reluctant to create more debt. And even Democrats support the notion that America’s European allies should be the ones taking the initiative in conflicts on their own borders.

WERE America’s political landscape to be radically redrawn by the November 2024 presidential election and financial support drastically cut, the question then would be whether Europe alone could muster enough cash and weapons to keep Ukraine going.

All this comes, too, at a time when the Ukrainian economy suffered more than a 30% decline in 2022 meaning that Kyiv needs even more money from the US and its other allies to keep the lights on so that the country can continue the fight.

While America, along with Britain, France, Germany and other allies, insist they will stay the course for “as long as it takes”, the costs are mounting at an ­incredible rate.

As The Economist magazine ­highlighted just last week, Ukraine’s friends should – in principle – have no trouble helping it outgun Russia.

“The combined GDP of Nato’s ­members is 12 times that of Russia, even after accounting for Russia’s lower prices. The difference is that Russia is willing to spend much more heavily on the war: ­military spending now takes up almost 40% of the national budget, far in excess of Western levels,” the magazine said in an article headlined “Why Western help for Ukraine is likely to diminish next year”.

By way of illustrating its case, it gives as an example the production of artillery shells which are used in vast quantities on the battlefields of Ukraine. While American and European production is soaring, with US output having risen from an ­annualised rate of 168,000 shells in the spring to 336,000 today, that is barely enough to keep up.

According to British estimates, Russia will produce one to two million shells next year – that is on top of a stock of around five million shells, new and ­refurbished. Cost, though, is the factor here, says The Economist – with Russia able to produce shells much more inexpensively because of “cheaper labour and materials, lower-quality products and lower profit margins for arms manufacturers, most of which are state-owned”.

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It’s against the backdrop of all of these myriad factors – from spiralling costs of the war to public opinion and domestic re-election battles right through to certain governments getting nervous over the ­implications of Ukraine one day joining the European Union – that continuing support for Kyiv is being impacted.

For his part, Putin has made little secret of his strategy in keeping up the pressure on Ukraine until the resolve of its allies falters and breaks. If what US secretary of state Blinken says is true and we have reached a “hinge moment in history” and the challenge from authoritarian powers is intensifying, then now is not the time to backslide in support of Ukraine, many would argue.

As for President Zelenskyy and the Ukrainian people, the months ahead are set to be difficult ones. Not only will they still be faced with pushing the Russian ­invaders from their country but they could well have to do it hampered by wavering or dwindling support from allies.