When the U.S. gave Ukraine 31 Abrams M1A2 tanks last week, officials responded by asking for fighter jets.

The U.S. is not ruling out the possibility of adding F-16s to the list of weapons and equipment provided to the besieged country, according to a Pentagon spokesperson.

Pentagon Deputy Press Secretary Sabrina Singh said,

This is a capability that would require training. It would require more people to come off the battlefield to learn a new — an entirely new system. And again, the Ukrainians have proven that they can learn complicated, complex, challenging systems. It is more — in terms of, like, the Abrams, it is more the sustainment, the maintenance when it’s on the battlefield. With the F-16s, again, another challenging system that would require training.

“And I’m not going to get ahead of any announcement because I don’t have an announcement today. So I’ll leave it at that,” she said.

No line drawn

When asked where the U.S. would draw the line, she said, “I don’t know that we’ve ever drawn a line. We’ve certainly — you know, we’re not going to take anything off the table here.”

The tanks the U.S. pledged will not be delivered for some time, since they are being built fresh for Ukraine rather than coming from existing U.S. stockpiles.

The action had the desired effect, however, which was to partner with Germany and encourage that nation to give its own Leopard 2 tanks to Ukraine.

It was not clear how F-16 jets would be given to Ukraine, as newly built or existing ones, if they were given at all.

But it does seem like the Biden administration, and maybe even Congress, are willing to give Ukraine just about anything it asks for as it fights Russia's 11-month-old invasion.

Will Russia retaliate?

Giving weapons and equipment to Ukraine is a way the U.S. can help an underdog ally hold its own against a world power, but will U.S. involvement lead to retaliation from Russia?

Russia doesn't have to attack the U.S. with physical weapons in order to show its displeasure. The specter of a cyberattack that could take out part or all of the U.S. power grid would be every bit as crippling as a physical attack, if not as destructive or long-lasting.

Biden doesn't seem at all concerned that Russia will attack us for helping Ukraine, but it's hard to know what he's thinking.

Without the $27 billion in military equipment from the U.S., plus billions more in direct aid and disaster aid, Ukraine would be in far worse shape right now than it is, if it hadn't surrendered to Russia already.

But how far is Biden willing to go?