Robert Hamilton is a research professor at the U.S. Army War College’s Strategic Studies Institute, a retired colonel and 30-year veteran of the U.S. Army, and an analyst on conflict and security issues in the former Soviet Union and the Balkans. It took a while, Hamilton says, for Ukraine’s allies to believe it could mount a sustained, effective resistance to the Russian invasion for long enough to get complex weapons like tanks to them, let alone to train them—or ultimately, to believe the Ukrainians could be effective with the weapons, rather than just get them destroyed or let them fall into the Russians’ hands. Western confidence in the wisdom of arming Ukraine has since grown considerably, Hamilton says—but the logistics, not to say the politics, of doing it have remained tricky.

Robert Hamilton: At the outset of the war, there was a lot of concern across the West about the risk of escalation between Russia and Ukraine. Of course, Russia helped provoked that by labeling any assistance to Ukraine as escalatory and destabilizing.

But as Russia pressed on, and as Ukraine increasingly demonstrated its ability to defend itself—and even to reverse some of Russia’s territorial gains—we’ve seen an increasing willingness among Western governments to accept more risk. And with that, we’ve seen an increasing willingness to provide more complex and capable weapons systems that take longer to learn how to use and that require more logistical support.

After the initial invasion, many Western governments fell into the unfortunate assumption that what came next would be a short war—that Russia would roll Ukraine—and this assumption stalled their eventual support efforts. Ukraine ended up surprising the world, not only with the tenacity of its resistance but with the competence of its defense. And frankly, Russia ended up surprising even itself with the incompetence of its offense.

As the war’s gone on—and I think the perspective now among most Western governments is that it’ll be with us for a long time—Western countries have shown greater confidence in Ukraine and, with that, a greater openness to investing in military support for it.

Valentine: Looking at European allies specifically, EU countries other than Germany have been relatively eager to send Leopard tanks to Ukraine—and have been pushing Berlin to let them do it. Why has Germany been so hesitant to send Leopards—or allow other EU countries to send them?

So it was important to the Germans that the U.S. would lead the effort to supply tanks—or at least that the two countries would co-lead this effort. Germany’s Chancellor Olaf Scholz made this quite clear: His country would not move on delivering tanks unless and until the United States provided some of its own. That would be an absolute condition for the Germans to send even the relatively small number of 14 Leopard 2s they’ve now agreed to send.

It’s true, meanwhile, that Germany wasn’t only hesitant to send Leopards; it was hesitant to allow other countries to send them. That’s because Leopards are German tanks. Germany isn’t alone in requiring permission for transferring weapons systems it develops to third countries. The United States does exactly the same thing. We call it third-party transfer authority. If a country buys a U.S. weapon, and that country wants to sell it in turn, the U.S. has to approve the transfer. So in that sense, there’s nothing unusual about Germany’s requirements.

“As a platform, the tank is the premier offensive ground maneuver weapon in the world. Enough of them, used correctly, could potentially change the course of the war. But two battalions of tanks won’t do that on their own. Whether the number that would is 300 or 200 or 150, it’s definitely more than 59. That said, I don’t expect this is the last we’ll see of Western tanks being supplied to Ukraine—if the Ukrainians show they can use the tanks well, even in the small numbers they’ve been supplied in.”

“It appears the U.S. has decided to transfer what would essentially be a Ukrainian battalion, and the U.K. and Germany have decided to transfer one company each. If the Ukrainians organize these tanks into an Abrams battalion and a Leopard battalion, deploy them in a focused way—in one sector of their defensive lines, likely in the East or the South—and use them properly there, they could exploit a breakthrough.”

“In offensive warfare, tanks are very, very good to have when your enemy has prepared defensive lines—with mines or other obstacles—and you’re able to hit those defensive lines with artillery and breach them with infantry. The tanks can then go through the breach and exploit it very quickly, flanking the enemy or moving in behind it. So if the Ukrainians use the tanks in that way, and use them well, they could make a real difference along some extent of the lines where they’re now faced off against the Russians in the East and South.”