There’s no denying Paul is obtuse, overly-focused on his myopic view of monetary policy, and about as well-suited for television as Nixon or Krugman, but in what way is he a “nut”?
As far as I can tell he's a 'nut' because (a) he thinks the War on Drugs is destructive to liberty, (b) he thinks the US is far too entangled in foreign engagements, and (c) doesn't buy into the propaganda of the Magic Money Man we know and love as the Federal Reserve.
Funny thing is that I pretty much agree w/ him on all these issues, and I'm not a nut.
I believe that the first part of your sentence spells out why he is a nut better than I ever could.