This country has no obligation to give Ukraine one cent.
That would be true if we hadn't convinced them to give up their 1000+ nuclear warheads and the intercontinental ballistic missiles to deliver them and something like 300 billion dollars worth of conventional weapons in 1994.
We could just give the Ukrainians 100 nuclear warheads, missiles to launch them, and the inflation adjusted value of the arms they transferred to us (more than $600 billion today) plus the value of the 900 other warheads. Once they were re-armed they could deal with the Russians on their own.
Of course that would put the whole world in a rather perilous situation.