Last week, the Biden administration sent another $400 million in defense aid to Ukraine.
It was the 15th such package and brought the total level of humanitarian and military aid to $7 billion since the war began in February.
The package included heavy artillery, including howitzers and High Mobility Artillery Rocket Systems (HIMARS), which have been crucial to slowing Russia's progress in the eastern part of the country.
More will undoubtedly follow.
There's no question this war has been illuminating. It's a rare (if tragic) opportunity for the United States and Europe to gauge the military effectiveness and vulnerabilities of a near-peer rival.
We've learned a lot about Russia's military - and in all candor, most of it has been pleasantly surprising.
It turns out Russia's best weapons aren't as advanced as we feared.
Its intelligence apparatus was an embarrassment from the start - badly misinformed and easily penetrated.
Its bureaucracy has been a hindrance, stalling its war effort with poor communication, bad analysis, insufficient planning, and inadequate strategy.
Those are all good things.
But in spite of all these failures and disappointments, Vladimir Putin hasn't been deterred.
Russia is instead making plans to quickly annex the territory it's won. And Ukraine and the West are gearing up for a long, grinding slog. Hence the latest aid package.
And so, amid all this, another key lesson has emerged for the defense community...
You can never have too much ammunition.
"That's what Ukraine has proved," says Wes Kremer, president of Raytheon Missiles & Defense. "It really is important not only to have that deterrence capability but to be able to have enough quantities. Because as we saw, stores get depleted very quickly."