I have had interest-free credit from vendors before, while other customers paid the sucker bad credit risk rate. Not for the amount Newt had, but zero interest rate lines of credit are neither illegal nor unprecedented.
Heck, many companies have 90 day terms and some have 120 day terms that are zero interest.
Also, remind me, again, what current elected or appointed office Newt or Newt's wife holds that would place him under the requirements of elected, appointed, or hired gov't employees? Oh, right, that would be NONE.
The author of the piece is either a nitwit or mendacious and trying to get the ignorant spun up.