US military support for Ukraine: what to expect after Biden?

On 9 January, the United States approved its 74th package of military aid for Ukraine, valued at $500 million, under the Presidential Drawdown Authority (PDA). This marked the final transfer authorised by Joe Biden's administration, which utilised a total of $19.35 billion from the support package approved by the US Congress on 23 April 2024. This funding included $7.8 billion for arms and military equipment that could be rapidly transferred from the Department of Defence’s stockpiles under the PDA and approximately $13.8 billion for weapons to be procured from the defence industry under the Ukraine Security Assistance Initiative (USAI) – see ‘The new US supplemental bill on Ukraine and the threat to confiscate Russian assets’.

Between late April 2024 and January 2025, the Biden administration approved five assistance packages under the USAI (using all available funds) and 17 PDA packages with a total value of $5.55 billion. Since the start of Russia’s invasion in February 2022, Washington has allocated $65.9 billion in military support for Ukraine.

Without another US support package or a significant increase in European involvement, Ukrainian armed forces will be unable to sustain an effective defence of their homeland. Donald Trump could utilise the remaining $2.25 billion under the PDA, allowing him to maintain the current level of US military support for Ukraine for another three to four months, providing time to develop and implement a new formula, should such a decision be made.

Commentary

• Over the past eight months, the United States has provided Ukraine with fewer weapons and military equipment, both in terms of quantity and value, compared to the same periods in 2022 and 2023. This is due to recruitment challenges and the depletion of older stockpiles of military equipment that the US Armed Forces could transfer without significant constraints. US support for Ukraine has concentrated on supplying artillery and rocket ammunition, anti-aircraft missiles, and aerial bombs, as well as supporting the operation of F-16 aircraft. Additionally, Ukraine has received 114 Bradley infantry fighting vehicles, 600 M113 tracked armoured personnel carriers, 212 Stryker wheeled armoured vehicles, eight 155 mm howitzers, 150 M1117 armoured vehicles, 3,000 HMMWVs, and a Patriot air defence battery.
• The Trump administration could utilise the remaining $2.25 billion from the PDA included in the most recent assistance package approved by the US Congress, enabling it to continue providing support for another three to four months. However, the Republicans have argued that the current approach to military aid has been exhausted, and a new formula is required. This could involve replacing direct assistance with low-interest or interest-free loans, a solution discussed by Republicans during the prolonged negotiations over the previous package, which Trump supported at the time. A significant challenge may arise from the need to secure Congressional approval for the next tranche of aid for Ukraine, which is likely to be more difficult than in April 2024 due to the weakened position of the Republicans in Congress and internal disputes within the party. An executive order issued by President Trump on his first day in office, suspending US development aid for 90 days pending a review, should not affect the already approved and ongoing military assistance for Ukraine, as these are legally distinct issues.
• Without further military assistance under the PDA from the Trump administration, Ukraine may struggle to sustain its current pace of military operations for more than four to six weeks. This is due to the schedule and nature of US deliveries of arms and military equipment over the past eight months, when support was provided in relatively small packages, preventing Ukraine from building substantial reserves. After this period, the effectiveness of Ukraine’s air defence and artillery fire is likely to decline sharply, as occurred in the first quarter of 2024. While this will not lead to a collapse of Ukrainian defence, it will increase the operational freedom of Russian forces. In the medium and long term, if military support is not maintained, or preferably increased, Ukraine will be unable to sustain an effective defence.