Yeah, them diddling with SS is one of my major fears. As a retired person, and while I don't depend entirely on it, it's a major chunk of my income. If I were in the UK or France and they cut off my SS, I'd have no way to replace that income as I have never worked abroad. The impact would be devastating. I know a number of people who have retired to the EU and UK already who are in the same situation. They'd end up homeless.
In my case it would be a matter of timing. If I relocate to France on my dual EU citizenship, it would be to be able to bring my daughter with me as an EU dependent. (I could, of course, retire to France as an American, but she'd have no way to accompany me on that route.) If we did the EU route to get there and then had to chose between citizenships I don't think I'd renounce, but if they took it away there could hypothetically be grounds for one hell of a court battle. If I wasn't an Irish citizen any longer I'm not sure what would happen to my daughter's status until she got her 5-year permanent residency card. If they took my SS.... Well, lets just hope this bill goes nowhere and is just a bit of grandstanding. I'm assuming there's going to be a pretty strong backlash against it.