For the last two years, Ukraine has fended off a full-scale Russian invasion with the help of unprecedented amounts of U.S. and European arms, materiel and other support. Crisis Group has encouraged Western partners to support the Ukrainian war effort, arguing that Russian victory in Ukraine would not only rob the country of sovereignty and undermine its territorial integrity, but also encourage further Russian adventurism and leave Europe poised for more conflict and instability. 

Yet, with the invasion’s second anniversary at hand, the U.S. commitment to that effort is in doubt. While the U.S. administration and a bipartisan majority in Congress support a major aid package that would make tens of billions of dollars available for new weapons shipments and other assistance, that may not be sufficient to pass the enabling bill into law. Encouraged by former President Donald Trump, the opposition Republican Party’s presumptive nominee in the 2024 presidential election, a small but powerful bloc of sceptics in the U.S. House of Representatives is keeping the new package bottled up. This group has disproportionate sway over the speaker of the House, Mike Johnson, who controls which bills can come to the lower chamber’s floor for a vote. Wherever his personal sympathies lie regarding the war in Ukraine, Speaker Johnson has thus far shown little appetite for bucking these of his colleagues. 

Opposition to the assistance is concentrated among Trump’s staunchest supporters in Congress. They have yet to offer a consistent or rigorous explanation for their posture. Some argue that the U.S. does not have the simultaneous capacity to arm Ukraine and deter China (others contend that it does); others have suggested that even with support Ukraine’s defeat is a foregone conclusion (it is not). A number, including Johnson, have argued that the Biden administration and Democrats in Congress must meet Republican demands with respect to managing migration at the U.S. southern border before the aid package can proceed. But a bipartisan Senate effort to present legislation that included many border enforcement policies pushed by Republican lawmakers never made it out of the upper chamber because it met with Trump’s and, ultimately, Johnson’s disapproval. Whatever the merits of that failed bill, it is not clear that any step the administration or Democratic legislators could take on immigration would satisfy the Trump faction, which sees disaffection with border policies as a winning issue in a presidential election year. 

Against this backdrop, opposition to the aid package seems more a manifestation of political fealty to Trump than an expression of strong policy preferences – although some detractors (such as Senator Rand Paul) have consistently advocated for the U.S. to pare down its international commitments. As for Trump’s own objectives, these have not yet fully emerged. Beyond a desire to deal the Biden administration a political blow, he appears to be setting the stage for realigning U.S. strategic priorities should he be elected. The implications for Washington’s transatlantic partners could be substantial. In addition to saying he would cut any remaining aid to Ukraine as part of an effort to force a peace deal between it and Russia (an approach that would likely leave Ukraine at the mercy of its far more powerful neighbour), the former president has also signalled an intention to distance Washington from its longstanding NATO allies. At a recent event, Trump even suggested that he would encourage Russian aggression against allies with lower defence spending, whom he sees as freeloaders taking advantage of U.S. generosity.

The tribulations of the current aid package are therefore significant on multiple levels. The failure to enable new assistance may prove decisive when it comes to Ukraine’s defensive efforts. At the same time, the inability of congressional supporters to push the package through, even though they appear to make up a majority in both chambers, offers insight into the strength of Trump’s hold on Republican legislators and the deference that they are likely to show him in matters of international relations if he is elected again. As strong a proponent of U.S. power projection as Senator Lindsay Graham has seemingly retreated from full-throated support for Ukraine in order to align himself with Trump. Finally, resistance to the Ukraine aid package could well prove a harbinger of deteriorating transatlantic security cooperation at a time of increasing instability on Europe’s eastern flank. 

Since February 2022, the U.S. has committed some $44.2 billion worth of materiel to Ukraine, over half of the more than $85 billion in security assistance transferred or otherwise committed by Western states. In addition, the U.S. has committed some $26 billion in loans and other economic support, with a far greater share, some $83.6 billion, committed by European institutions, with additional funds from other states. The majority of U.S. security aid to Ukraine has been obligated by what Washington refers to as supplemental appropriations bills, a type of legislation separate from the regular spending bills Congress passes annually. 

Two main pots of money in the supplementals have been key to military support for Ukraine. The first is what is referred to as the Presidential Drawdown Authority, which allows the president to immediately transfer Department of Defense stocks to other nations when the president determines an “unforeseen emergency” exists. In consecutive supplemental bills in 2022 and 2023, Congress lifted the cap on this authority, which typically is $100 million a year, allowing President Joe Biden to use it dozens of times. Since 2021, the Biden administration has sent Ukraine $23.9 billion worth of U.S. military equipment by the drawdown route. 

The second main funding stream is the Ukraine Security Assistance Initiative – established by an act of Congress in 2015 (after Russian troops invaded Crimea and established separatist statelets in parts of Ukraine’s eastern Donbas region) and expanded in 2022 and 2023. The Initiative allows the secretary of defense to provide security assistance to Ukraine, including through contracting with private firms to manufacture new arms and ammunition. The U.S. has spent approximately $19 billion through this initiative during fiscal years 2022-2024, the vast majority of it going to U.S. defence contractors. 

 The Biden administration has asked Congress to fund more assistance for Ukraine, as part of a $106 billion supplemental funding request it made on 23 October 2023. The proposed package includes funding for Israel, border security and Taiwan as well. For Ukraine, the president’s proposal to increase military assistance includes $18 billion to replenish Department of Defense stocks, another $12 billion for the Ukraine Security Assistance Initiative and an increase on the cap for the Presidential Drawdown Authority to $7 billion. It also requests additional amounts for non-military assistance. 

At the beginning of 2024, meanwhile, the Biden administration said the last of the money available for military assistance was gone. Although there is approximately $4 billion left under the drawdown cap, Department of Defense officials consider the risk to U.S. military preparedness too high to keep dipping into U.S. weapons stocks without funding to replenish them. 

The administration insists that until Congress passes another supplemental appropriations bill, it will announce no new tranches of military aid. That said, some transfers under previously announced tranches will continue. Because the Pentagon’s procurement takes time, not all the equipment it has purchased has been delivered. Ukraine is scheduled to receive more shipments over the next two years, albeit slowly and unevenly. The transfers will also be much smaller than in the past. 

The question of maintaining U.S. assistance has become ensnared in Washington’s polarised politics. Biden sent Congress his proposal for supplemental funding in October, which included provisions addressing immigration across the southern U.S. border, since he believed that Republicans would not pass a new bill without such measures. 

Over the course of several subsequent months, Democratic and Republican senators worked together to develop legislative changes related to border security and immigration, putting forward a bipartisan bill in early February. Senators who negotiated the bill insisted that it represented a rare instance of compromise and progress on this perennially fraught issue, but immigration hawks argued that it was riddled with loopholes, and Trump’s allies rallied against it. Some (including Trump himself) said they simply were not willing to give President Biden a win on immigration so close to the November election. Speaker Johnson said the bill would be “dead on arrival” in his chamber. 

With opposition mounting among Senate Republicans, Senate Democrats split the bill, putting just the foreign assistance portion up for a vote. The Senate passed the legislation, which contains $48.43 billion in U.S. military support for Ukraine through December, by a vote of 70-29 on 13 February, sending it over to the House. But on 16 February, the lower chamber went into recess until 5 March, leaving the legislation untouched. In the meantime, Trump and his surrogates continue to make their opposition clear. Trump called aid in the form of grants to Kyiv “stupid”, insisting that support be structured as loans while giving the strong impression of simply wanting it to end. 

These tactics may well prevail. Although there appear to be enough Ukraine supporters on both sides of the aisle to pass the legislation, Speaker Johnson’s role as gatekeeper could prove decisive. However much traditional Republican hawks may favour the bill, Trump’s influence over the congressional Republican caucus as a whole appears to be growing as the election draws closer. 

This influence is especially pronounced in the House, where Republicans have a slim majority, and a small Trump-aligned faction calling themselves the Freedom Caucus wields substantial power. The reason why dates to early 2023, when as part of exhaustive efforts to keep the speakership, former Speaker Kevin McCarthy made an unorthodox deal with this group whereby any one member of Congress could make a motion to vacate the speaker’s chair upon a majority vote. In October, members of the Caucus used this tool to call a vote for McCarthy’s ouster, which they won when the Democratic minority voted with them. As McCarthy’s successor, Johnson inherited this arrangement. Hanging over the speaker like a sword of Damocles, the rule has a crippling effect on the legislative process, forcing him to tread carefully lest this tiny margin of the party move to vote him out. 

If Ukraine does not get more U.S. military aid, it may find itself struggling to sustain its fight before too long. Battlefield assessments are bleak. Officials in Washington agree that it is Western weapons and funds, especially those from the U.S., that enabled Kyiv to stave off the worst while also helping achieve unexpected gains at earlier junctures in the conflict. Those gains inflated hopes that Ukraine’s 2023 counteroffensive could force Russian troops back and motivate the Kremlin to be ready for talks that could lead to a sustainable peace. Instead, Kyiv’s forces faced a dug-in Russian defence and made little progress.

Now, despite significant losses of personnel over the last two years, it is Moscow that has the momentum and is pressing Ukrainian defences. Supply shortages caused by Washington’s failure to pass a supplemental funding bill and the sluggish ramping-up of defence production on both sides of the Atlantic are aggravating scarcity and compelling Ukraine to ration ammunition. Ukraine’s defence minister warned in January that the shortage of artillery shells was cause for concern. In the battle for the strategic eastern town of Avdiivka, from which Ukrainian troops had to withdraw in mid-February after months of intense fighting, Russia’s artillery outgunned Ukraine’s five to one. If Kyiv is to keep going, its backers must transfer more ammunition and equipment, including increasingly critical 155mm shells, as well as air defence systems. Ukrainian forces are already forced to make choices about what cities or other areas to defend with the interceptors they have. Without interceptors, the country will be unprotected from aerial attack – a posture that would almost surely be unsustainable. 

In theory, yes, but none that seems altogether reliable. When the House and Senate return from recess at the end of February, the first task will be to pass a fiscal year 2024 spending bill in order to avoid a government shutdown. Speaker Johnson has made clear that this item will be his top priority upon return. If there is a shutdown, then the space and time for discussion of Ukraine will narrow yet further. 

While there are avenues that would allow lawmakers to advance the Ukraine package even without the speaker’s acquiescence, the obstacles are significant. The first, which is being floated by House Democratic leadership, is a discharge petition, which would allow Democrats, with the help of sympathetic Republicans, to go around Speaker Johnson to force a vote on the Senate supplemental bill. There are a number of procedural hurdles in taking this route – most previous attempts have failed – but the key requirements include finding a sufficient number of Republicans willing to defy Trump to join a bipartisan majority and enduring a waiting period during which that coalition can be pried apart. The Wall Street Journal has published a useful summary of the ins and outs of this process (which the Democrats have initiated), as well as other potential manoeuvres. 

Other options remain, but the odds for them are similarly low absent resolution of the political challenges that have bottled up the pending legislation. One option floated is to put forward an omnibus bill, which would include government spending for the rest of fiscal year 2024 (ie, through the end of September) with the Senate’s Ukraine supplemental as a rider. That route could face the same political problems Ukraine funding has right now, however; Trump’s supporters in the Freedom Caucus might well prefer to shut down the government than to support assistance on terms they find uncomfortable. Another is even less ideal: the appropriations committees could increase assistance to Ukraine in the base budget established by the new spending bill being negotiated to avert a shutdown (eg, raising the annual Ukraine Security Assistance Initiative total or the cap on the Presidential Drawdown Authority). But this option could again founder on opposition, with Republicans seeing it as an attempt to sneak in supplemental funding through the back door. It is also possible that Speaker Johnson will change his mind about the Senate supplemental bill, though that seems most unlikely. For now, some Republicans in Congress are trying to scale down the Senate version in hopes of garnering majority support for a smaller package. 

Executive branch officials and members of Congress emphasise that the supplemental funding provided over the last two years is what has enabled the flow of arms, ammunition and other assistance to Ukraine’s front lines. The Biden administration has stressed that “there is no magic pot of money” and no “Plan B” should Congress fail to act. Without additional funding, the transfer of materiel to Ukraine will grind to a halt, dealing a perhaps fatal blow to the war effort. Already, the Biden administration has directly blamed the Ukrainian withdrawal from Avdiivka on Congressional inaction. 

Absent Congressional action, the Biden administration has a handful of options to continue providing Ukraine with a minimal amount of security assistance. The Department of Defense, relying on authorities that help build partner capacity, could focus on efforts like training Ukrainian soldiers. The Department of State could provide Kyiv support for specific needs such as border security and law enforcement. The president can authorise transfers of U.S.-made items from third parties to Ukraine – that is, other countries can buy U.S. weapons and ammunition and pass them along to Ukraine, as some European states are doing. But officials emphasise that at current funding levels these mechanisms offer just a small fraction of what the supplemental funding bills would provide and what the Ukrainian war effort requires. 

Similarly, the much-discussed prospect of using seized Russian assets would not be a practical way of bridging the gap. Such a move would raise significant issues under international law that would need to be carefully negotiated, which is one reason that authorities in Europe (where the bulk of the assets are held) have been reluctant to entertain proposals that go beyond the diversion of earnings on invested assets. Even under more expansive notions of how the assets would be used, there appears to be a wide consensus (including in the U.S. Congress) that they should be applied toward reparations – ie, as a way to charge Russia for the damage it has inflicted on Ukraine – and not for military support. 

As of now, no other state can match the U.S. in delivering military aid on short timelines. Even though European military aid allocations for Ukraine are only €2 billion (about $2.16 billion) less than those of the U.S., the latter (unlike the EU and its member states) has vast stocks from which it can draw. Since the all-out invasion, Washington has implemented quick-turn contracting for new materiel, which Europeans have been slower to ramp up. Even though some European states are purchasing U.S.-made equipment to contribute, procurement can take time. The EU set a goal of sending one million shells to Ukraine by March via a mix of stockpile drawdowns, production and foreign purchases, but it looks set to reach only half that target. 

Europe has struggled in other ways as well. EU members have clashed over the sometimes competing priorities of supporting Ukraine, on one hand, and ensuring that the European defence industry benefits and grows from it, on the other. Thus, they have been cautious about using pooled European funding to purchase arms from the U.S. and other producers, although individual countries have purchased U.S.-made weaponry. EU member states would also struggle to make up for training, intelligence-sharing and other non-material support the U.S. has provided Ukraine if, say, a future Trump administration decided to end it. On a February visit to Washington, German Chancellor Olaf Scholz, whose country is the second largest supplier of military aid to Ukraine, stressed how hard it would be for Europe to replace U.S. assistance. “Let’s not beat around the bush”, he said. “Support from the United States is indispensable”.

Perhaps, but the EU and its member states should not accept that proposition at face value. Rather, they should take bilateral measures to reduce Ukraine’s shortage of ammunition, for example by digging deeper into national stockpiles, placing procurement orders and buying ammunition directly on the international market (measures the EU’s foreign policy chief, Josep Borrell, reportedly called for in a private letter to member states). An emergency scheme, spearheaded by the Czech Republic, to raise $1.5 billion to buy shells from overseas is promising and worthy of emulation. Moreover, EU member states should move urgently to resolve disputes that are holding up the next €5 billion (over $5.4 billion) tranche of military assistance for Ukraine. Over the longer haul, the EU will also need to do more to provide long-term funding for military supply to Ukraine and revive European weapons manufacturing – steps that are crucial for supporting Ukraine, developing Europe’s defence industry and allowing the bloc to better provide for its long-term security.

The more that Europeans can do to help Ukraine now, and to set themselves up for a well-defended future, the better. Not only are these worthy goals in their own right, but pursuing them will also provide fodder for proponents in the U.S. Congress who argue – correctly – that enabling more U.S. assistance to Ukraine now can only help prepare the ground for a future in which Europe plays a greater role in protecting regional security, for the benefit of both its own interests and those of its longstanding transatlantic partners.