Where do the dollars originate from? I assume it’s from the military budget which has already been approved by Congress for this fiscal year. If republicans take the house this go around I could see the next budget iteration cutting off Ukraine.
congress has to appropriate money for us to be able to give aid to ukraine. in most cases, that money is then given to the dept of defense and the dept of defense transfers weapons deemed to be worth that amount to ukraine. the money allocated also has to pay for the transport and any refurbishing of the weapons. and i'm pretty sure any non-materiel assistance we deliver like satellite intel is also charged to aid packages.
the weapons given are a mix of old stuff that we probably would never use again anyways and new stuff that is in active production. in the former case, the actual value of that equipment to our military is almost quite a bit less than the paper value they realize when congress gives them money to send it to ukraine.
we also sometimes give ukraine money to purchase weapons themselves or pay other countries to deliver weapons to ukraine (like today it was announced that holland and the u.s. are going 50:50 on funds to help the czech republic refurbish and donate some old soviet tanks they have kicking around). but i think those allocations are much smaller than what we send directly.
we've only sent like 18.9 billion in military aid. it's not very much money.