If this doesn't just die a death and she actually starts the process, I think it'll backfire on her long before it gets to court. It'll turn into a big free speech thing and people who haven't bothered before will start looking into her. On top of that people will be going through her Twitter and she'll be bombarded with her old tweets and variations 'how come it's ok for you to say X but you're suing people for saying something far milder about you?'.