Nationalizing in the traditional sense is not the solution, indeed, but rather hold the platform up to the letter of the constitution. This right now is not exactly possible given that "twitter is a private company", therefore arguably if one puts it in the hands of the government, you have the double-edged sword of potentially being abused by the government, and on the other hand the solution i forementioned on holding it accountable given that it would become public under the law. However, just like with any other gov. institution, being held accountable is more often than not up to the people through their civic initiative and probably not something that the government will do out of interest. So in this regard in US it could work given the nature of the constitution, whereas in other countries Twitter would just become a propaganda machine (isn't it one already?).
Supreme Court Justice Clarence Thomas suggested extending common carrier legislation to cover social media platforms. That would essentially prevent them from censoring any content legal in the US.
Thanks for the link, I remember hearing about Clarence Thomas' take on this subject but I never took the time to study it. My personal opinion (before reading the material above) is that the "core issue" stands on the S230 "loop-hole" (I don't want to use the term 'abuse' given the negative connotation ... so far it[S230] has been a net good since it made the internet grow so much since 2007, but things have started to change with the rise of monopolistic corporations) giving companies both privileges with less responsibility than should necessary. At least in principle a Bill of Rights should exist, especially considering that places like Twitter are considered fairly often under the law (think court cases) 'public spaces'. Therefore in my mind if the public street is a place where i can speak freely, so should one be able to on Twitter/any other such deemed public space.