This is true; but nowhere did it say that we had either to bankrupt ourselves doing so or kick off WWIII in the process. There us an implied limit to all such agreements; and has been ever since the cluster F**k if treaties that auto-sucked all those nations into engaging in WWI. In other words, unless it really means the included destruction of Europe then we need to draw the line with what we have already done by way of ruinous fiscal involvement, and back off.
At this point it's NATO's problem as we have already done enough. It's just the Ukraine's misfortune to have been attacked by Russia while the United States has got the weakest and most incompetent president in the Oval Office of the United States of America . . . ever.
On another note . . . just as happened with the government of South Vietnam, we KNOW that an untold amount of funding going to Ukraine to fight the Russians is actually going straight into the bank accounts of corrupt Ukrainian officials and their business cronies. Just as happened with South Vietnam and then Afghanistan and -- let's face it -- Iraq, as soon as we withdraw our 'support' the Ukraine IS going to fall anyway. It might as well happen now as latter while we halt that one massive fiscal bleed of OUR treasury.