Arnold displayed the Conan sword and used it as a metaphor to describe how the United States can triumph over the Capitol rioters who want to tear this country apart. You gotta hear his description ... it rings true.

The former Cali Guv, who was born in Austria 2 years after the Nazis lost WWII, compared the Nazis to the rioters.

He talked about Kristallnacht -- The Night of Broken Glass -- where the Nazis went on a rampage against the Jews in 1938 and then said the Proud Boys were the Nazi equivalent.  He says last Wednesday was our Night of Broken Glass.

Arnold called the elected officials and other leaders who have been empowering Trump "spineless," saying they were too cowardly to stand up to the worst President in our history.

And, Arnold offered something interesting ... an understanding of what's behind the rioters.

He explained something he told Harvey during an episode of "Objectified," where he said as a child his dad was a failed Nazi supporter who lost the war, became a drunk and was physically abusive to young Arnold. He said his dad was like other dads in his neighborhood -- angry and abusive. He's clearly comparing the failed Nazis to the insurrectionists who invaded the Capitol.