This has already happened in Argentina. They took all the 401K’s and they gave Government Bonds paying a paltry 2%. Don't think it can't happen here because they have already thought about it and had hearings on it right after Obama took office.
Believe it or not, Argentina was, at one time, the third wealthiest country in the world, with a huge middle class.
Then the socialists took over. A hundred years later, they haven’t recovered.