Interesting, I figured it was another budgetary item needing funding approval. But, private donations in modern USSA will quickly become a very public media hit list!
No doubt about that as the opposition will be clamoring to get the list of donors and go after them. I did look up the issue of funding and I was partially correct. Besides private donations, state and local funding can be used to build the library (future revenue based on tourism and such) and the library is then turned over to the federal government (National Archives and Record Administration) for future maintenance of the physical property as well as making the different types of media (i.e. documents, audio, film, etc...) available to the public.