Now that the House of Representatives, acting in an unusually bipartisan way, finally passed a $61 billion aid package for Ukraine, the big question is what the Ukrainians should spend it on.

This aid comes not a minute too soon. Russia has been gathering momentum both on the ground and in the air, threatening a summer offensive that could crack the Ukrainians’ lines and threaten their major cities. These include Kharkiv — the major city nearest to the Russian border — and possibly Kyiv itself, forcing the government of President Volodymyr Zelenskyy out of the capital.

Central Intelligence Agency Director William Burns, a former ambassador to Russia, understands Russian President Vladimir Putin well. Burns said last week that unless the new tranche of U.S. aid was forthcoming, Ukraine was in danger of losing the war within the year. But he also said, “with the boost that would come from military assistance, both practically and psychologically, the Ukrainians are entirely capable of holding their own through 2024 and puncture Putin’s arrogant view that time is on his side.”

So, with the $61 billion of “forgivable loans” approved this week by the Senate and White House, what are Ukraine’s most crucial needs? How fast can the pipeline move more weapons and ammunition into the hands of Kyiv’s brave, overachieving military?

The good news is that both the U.S. and European defense establishments have been primed for this moment over the past months. My successor as supreme allied commander at the North Atlantic Treaty Organization, General Chris Cavoli, has said that it is largely a matter of turning on the spigot once President Joe Biden signs the aid bill. Cavoli’s vast command — eight full battlegroups in Eastern Europe alone — is poised to swing fully into action to deliver assistance.

Fortunately, nearly 90% of money for Ukraine will be spent on purchases from the U.S. defense industrial base. This means that procurement and logistics should run relatively smoothly down well-trodden paths. Storehouses in Europe — run by U.S. European Command and our NATO partners in Germany, Poland and other sites in Eastern Europe — are already full of weapons, particularly artillery shells, that could move quickly into Ukrainian hands.

At the top of the list will be replenishing Ukraine’s air defenses.

This means more surface-to-air missiles, ranging from the smaller systems like the National Advanced Surface-to-Air System (NASAMS) and the MIM-23 HAWK systems, to the big Patriot batteries that proved so effective in defending Israel during the Iranian air attack earlier this month. The Patriots and even larger Terminal High Altitude Defense systems (THAAD) can defend against Russian cruise and ballistic missiles over broader areas. These systems will protect not only civilians and critical infrastructure like the electric grid, but will be useful against Russian aircraft.

Next on the shopping list will be artillery ammunition.

All along the hundreds of miles of battlefront separating the combatants, daily artillery duels are being fought. Russia is getting the better of the Ukrainians through sheer volume of fire. As in World War I, defensive trenches can help hold off the waves of cannon-fodder foot soldiers the Russians use (including many conscripts and convicts), but their artillery can pin down and ultimately overcome the dug-in Ukrainians. The most pressing need for the Ukrainian artillery is millions of traditional 155 millimeter howitzer rounds, alongside ammo for smaller-caliber guns.

Ukraine will also want to use the funds to help finally get the 45 or so F-16 fighters previously promised by the West into the skies.

These versatile combat aircraft are capable of solid air-to-air defense against Russian fighters and bombers; pinpoint air-to-ground attacks against Russian troops in the field and in their trenches; and electronic warfare and jamming that can deceive and defeat Russian cruise missiles. Ukrainian pilots have been training for months to fly them.

Another high priority will be long-range surface-to-surface missiles.

The U.S. Army’s High Mobility Artillery Rocket System (HIMARS) is mobile and lethal. It can use precise targeting data at ranges of 50-plus miles, and has been deployed with great effect on the Ukrainian battlefield. Even better is the Army Tactical Missile System (ATACMS), a ballistic weapon with ranges of 150-plus miles. Both can strike behind Russian front lines and destroy logistics centers and command-and-control hubs, notably in Crimea.

The war in Ukraine has also become the first lengthy conflict in which drones are playing a major role.

Unmanned aerial vehicles have been crucial for the Ukrainians in stopping Russian advances. These drones rely on exquisite command and control — much of it provided over the internet and connected to constellations of satellites. This may be less glamorous than ballistic missiles flying toward Crimea and fighters swooping down on Russian forces, but it is just as critical. The U.S. loan package could allow the Ukrainians to field a stronger offensive drone force with commensurate cybersecurity abilities.

Given that this $61 billion is under 7% of the massive U.S. defense budget, it represents excellent return on investment for U.S. taxpayers. Nearly all of the money will be spent back in the U.S., providing jobs and helping the economy, and it will help decimate the military capability of an aggressive dictator without putting a single U.S. service member at risk. These funds, along with the billions of dollars the European allies have already provided and pledged (in total military and economic assistance, the Europeans have given far more aid to Ukraine than the U.S.), give Ukraine a fighting chance.

In 1941, UK Prime Minister Winston Churchill said to the U.S., “Give us the tools and we will finish the job,” referring to defeating Nazi Germany. Today, another rapacious foe is attacking a sovereign European state and seeking to undermine Western values globally. Putin must be stopped, and with the right set of tools provided by the U.S. and Europe together, Ukraine too can do the job.

James Stavridis is a Bloomberg Opinion columnist, a retired U.S. Navy admiral, former supreme allied commander of NATO, and dean emeritus of the Fletcher School of Law and Diplomacy at Tufts University. Stavridis is also vice chairman of global affairs at the Carlyle Group. He is on the boards of Fortinet, NFP, Ankura Consulting Group and Neuberger Berman, and has advised Shield Capital, a firm that invests in the cybersecurity sector.

Related Articles

Zeynep Tufekci: This may be our last chance to halt bird flu in humans and we’re blowing it

Adam Minter: The cost of youth baseball rises and rises — and prices many kids out

Lisa Jarvis: You’re not imagining it. Your allergies are getting worse

Mark Gongloff: Wildfire smoke is coming for the U.S. again. We’re not ready.

Rebecca Haw Allensworth: You don’t need to own an iPhone for the government lawsuit against Apple to benefit you