I don’t know...if it’s limited to US citizens caught on foreign battlefields, it’s hard to imagine anyone but Muslim fanatics coming into its scope. However, if it includes citizens incarcerated within the US, then I really fear we are close to the precipice. There’s a reason McCain/Feingold was overturned by the SCOTUS - is McCain up to his old anti-constitutional tricks?
From reading the text of the bill, anyone, within the US or outside the US, citizen or non-citizen, who is deemed to have materially supported hostile actions against the US government, can be detained indefinately.
The problem is, the President just has to say you’re an enemy belligerent, and nobody ever hears from you again.
Our biggest fear has to be: will they abuse their power.