Forget the Impoundment Act -- this is a Constitutional issue. The Supreme Court ruled in 1975 that the President is required to carry out the full objectives or scope of programs for which budget authority is provided by the United States Congress. Shuttering USAID, as Trump and Musk have done, goes way beyond mere line item impoundments.
However, they claim that USAID was spending far too much on projects that were not in line with their objectives. Not even Congress can create an agency that is fully autonomous with zero oversight from anyone within the government.
Whether that argument would hold up in court remains to be seen, of course.
That's just one example. Hamas has been receiving funding for years, despite their less than decent track record of using the money for it's intended purpose.
Yeah this was totally debunked, I believe the programs that were said to be "going to terrorists" were actually promoting women's literacy in Afghanistan.
All of these agencies had multiple levels of oversight both within the executive and through congress. Trump eliminated inspectors general positions providing oversight.
The executive branch doesn't get to interpret what spending is in line with the laws passed by Congress.
> Although one commentator characterizes the case's implications as meaning "[t]he president cannot frustrate the will of Congress by killing a program through impoundment,"[2] the Court majority itself made no categorical constitutional pronouncement about impoundment power but focused on the statute's language and legislative history.
The current SCOTUS majority isn't afraid to overturn 50 year old precedents. Given they overturned Roe v Wade, why not Train v City of New York too?
But they don't strictly speaking have to overturn it, just limit its scope of application somehow. For example, Train was about grants to the states – SCOTUS might rule the Congressional Budget and Impoundment Control Act of 1974 unconstitutional, and decide that the President has the right in general to impound appropriated funds, but they also might follow Train in carving out an exception to that general right for grants to the states.
https://en.wikipedia.org/wiki/Train_v._City_of_New_York