YouCut is a fantastic idea. It's ridiculous we don't have more direct representation given the ease with which we can collect peoples' opinions these days. I say let them cut NSF. Sure, I'll lose my funding, my grad students will have to find another PI, but we'll save a fraction of what we need to balance the budget. Oh sure, we'll have eliminated the very instrument for creating new wealth for America in the future, but hey, it's what Americans want.
I don't think we have much to really worry about though. Even if Americans stupidly target scientific infrastructure for the future I think their representatives will continue to fund it, just as they will always fund Defense research.