I don't agree with the premise that the US is somehow forcing the Ukrainians to fight for us. I'd point to Afghanistan as an example of the fact that we can't force anyone to fight for their own land if they don't fundamentally want to as a society. I'd also argue that stopping the Russian advance greatly benefits everyone who doesn't want to be tortured in a basement.. By all accounts, life under Russian occupation really sucks, that's why they are fighting against them. If we stop sending a few percentage points of our defense budget, putin gets rewarded, aggression is normalized (risk of China becoming more encouraged to act on their dozens of border disputes) and many more Ukrainians die. They will fight to the last inch of Ukraine whether we help them or not, I'd rather see Russia lose.