Your comment does not make sense. We supplied them with weapons before the war broke out. They managed to stop the Russian attack, even roll them back from near Kiev.
So, they have managed to stymie the Russians, so far, but it is not like they are at the edge of Moscow.
Your comment is like saying: The Soviets stopped the NAZIs at Moscow, so they don't need any more Dodge trucks, food, fuel, or steel to build tanks, right?
Studebaker US (US-6?) World War II military truck (mostly used by the USSR), at Łańcut, PolandIt is worth remembering that, by the time Germany invaded the Soviet Union in 1941, the German military had already conquered Poland (with Soviet assistance), the low countries, France, Denmark, Norway, plus Yugoslavia and Greece (IIRC). German conventional forces were therefore an obvious 'world class' threat; Russia's current conventional forces most definitely are not, although the country's nuclear forces apparently remain the largest (and most threatening) on earth.
It is also worth remembering that the vast majority of the aid provided to the Soviets by the US, was delivered when both countries were formally at war with Nazi Germany (i.e., after December 1941). Ukraine is currently at war with Russia - quite obviously, the US is not, and it would be the height of foolishness to change that.
In summary, there were vital American interests at stake, when the US aided co-belligerents in their mutual war against Nazi Germany. Today, in contrast, this country is not at war with Russia, and has no vital interests in Ukraine that would justify any American action that risks nuclear war...