I wonder if Google could be encouraged to make and keep a backup of all of the available US data. They are perhaps the group that can do this most easily. They may already have a copy of much of it, whatever is on the web, given that they cache so much data. Keeping the data would be in the spirit of its vision "to organize the world's information and make it universally accessible and useful." And it could be an excellent business investment should the US government ever delete its data.