If the US stops supporting Ukraine and Russia comes to NATO’s borders, it will have to act in accordance with NATO's Article 5 and pay with the blood of Americans.
Source: John Kirby, White House National Security Council Coordinator; White House
Details: Kirby noted that Russian President Vladimir Putin is counting on the US to stop supporting Ukraine. This will be a big gift for him.
Kirby said if Putin gets Ukraine, he will be on NATO’s doorstep. "And as I said the other day, if you think the cost of supporting Ukraine is high now, think about how high it’s going to be in national treasure and in American blood if we have to start acting on our Article Five commitments."
He also noted that the Russian president had expected such a development from the very beginning of this war because he did not believe that the West or NATO could stay united or that the United States had sufficient staying power.
Quote from Kirby: "If you care about our national security, you ought to see Mr. Putin for what he is, you ought to see Russia for what it is, and realise that helping Ukraine – and they’re not asking for boots on the ground – helping them win this war is very much in our national security interest and in the national security interest of all our allies in Europe."