Drastic oversimplification.
The space program has been an easy target for politicians of both parties who have their own ideas of where the money ought to go.
NASA defends against this by spreading its activities to as many congressional districts as possible, but it's still a problem every year.
We have also had individual politicians of both parties who have pushed the space program who aren't there any more, but some still are. Maybe new ones are coming on board. We'll see.