The Biden administration's constant dithering over supplying weapons to Ukraine is proving to be a decisive factor in the Ukrainian military's decision to delay its long-awaited spring counter-offensive against Russian forces.
Since the end of last year, when the Ukrainians inflicted a series of humiliating defeats against their Russian foes, Kyiv has been warning that it is in urgent need of fresh supplies of military equipment from its Western allies if it is to continue its campaign to liberate Ukrainian territory from Russian occupation.
In particular, the Ukrainians say they are in urgent need of replacements of tanks and other heavy armour, long-range missiles and aircraft - including F-16 fighters.
While the U.S. and its allies have pledged to provide limited supplies of weapons, however, the slow pace of delivery has prompted the Ukrainians to conclude they have no option but to delay their offensive until they are fully equipped.
The scale of the challenge facing the Ukrainians was highlighted by President Volodymyr Zelensky, who said his country is still awaiting the delivery of promised military aid from its Western allies, which was holding up Kyiv's plans to launch its much-anticipated counter-offensive.
Speaking at his headquarters in Kyiv, Zelensky described combat units, some of which were trained by Nato countries, as being "ready", but said the army still needed "some things", including armoured vehicles that were "arriving in batches".
"With [what we already have] we can go forward, and, I think, be successful," he said in an interview for public service broadcasters who are members of Eurovision News, like the BBC. "But we'd lose a lot of people. I think that's unacceptable. So we need to wait. We still need a bit more time."
One of the key reasons for the delay is the Biden administration's hesitancy about providing Kyiv with the firepower it requires to defeat the Russian occupiers, which has been a constant feature of its response to Russia's unprovoked invasion of Ukraine.
While U.S. President Joe Biden has constantly pledged his support for Kyiv, his rhetoric has invariably failed to result in providing the Ukrainians with the military support they require. Even when, as happened earlier this year, the White House reluctantly agreed to provide Ukraine with Abrams tanks - a move that was only approved after Washington came under intense pressure from allies such as Poland - the slow delivery timetable has made Ukrainian commanders despair that the equipment will ever actually arrive.
In recent months Ukraine has taken delivery of German-made Leopard tanks that have been donated to the Ukrainian cause by frontline European countries such as Poland. The Leopards, though, are arriving from eight different countries and fire different types of shells, which means the Ukrainians cannot buy munitions in bulk.
As for the promised Abrams tanks, U.S. officials readily admit that the Abrams are months away from arriving, as the Pentagon looks at its stocks to see what it can send.
In a recent interview with Foreign Policy magazine, Sasha Ustinova, a Ukrainian lawmaker, confirmed the U.S. military had delivered far less than what Valeriy Zaluzhny, Ukraine's top general, had asked for from the Pentagon. U.S. military aid is only arriving piecemeal as the Biden administration warns it is nearing the end of its ability to provide weapons that can be pulled off of the Pentagon's shelves to give to the Ukrainians.
Ustinova said that Ukraine hoped to begin the offensive in April, but the lack of weapons has pushed the launch date back indefinitely.
The Biden administration has been even less forthcoming with regard to Kyiv's request for F-16 fighter jets and long-range missiles that can destroy targets deep within Russia. The White House is reluctant to provide such weaponry for fear of provoking Russian President Vladimir Putin into escalating the war further.
With the White House refusing to provide Ukraine with long-range weapons that are capable of striking targets within Russia, the Ukrainians are increasingly resorting to making their own homemade weapons to fill the gaps in their arms supplies.
Recent reports have revealed that Ukrainian engineers have designed a "people's missile" using similar technology to the German V1 "doodlebug" rocket that terrorised London during the Second World War, and which has twice the range of the US-supplied HIMARS rocket systems.
In addition the Ukrainians have been busy developing their own fleet of long-range drones, which can carry payloads of 300 kilograms and fly hundreds of kilometres, depending on their configuration.
Having the ability to produce their own weaponry certainly allows the Ukrainians a degree of flexibility in choosing their targets, a luxury they were not allowed when they were obliged to accept the constraints imposed on their military operations by the West.
Even so, there are mounting concerns that without the heavy firepower that Ukraine's supposed Western allies can provide, Kyiv's ability to launch its spring counter-offensive will be severely diminished.
Certainly, any delay in the Ukrainians launching their offensive will only help to convince the Kremlin that, despite all the setbacks it has suffered over the course of the past year, it may still end up winning the war.
Con Coughlin is the Telegraph's Defence and Foreign Affairs Editor and a Distinguished Senior Fellow at Gatestone Institute.