How can a lone wolf terrorist be stopped? Judge Andrew Napolitano pointed out this morning that there's a big difference between gun rights in the United States and Canada.

Judge Nap: Beheading Attack Illustrates Importance of Gun Rights

Napolitano said loners with guns are a "devious" way for terrorists to strike.

"It's one guy getting out of a car and starting to shoot. What is the best deterrent to that? An armed citizenry. People able to protect themselves. We have a Second Amendment in this country. They do not have the equivalent of that in Canada," said Napolitano. 

The attacker, now identified as 32-year-old Michael Zehaf-Bibeau, was not stopped until he made it all the way into the Parliament building. He nearly got to lawmakers, but was shot dead by a heroic Sergeant-at-Arms

Steve Doocy and Napolitano also highlighted the state of Oklahoma, where a company executive with a firearm was able to stop the beheading suspect before he could murder more people about a month ago. The heroic employee was also a sheriff's deputy.

The soldier who was shot and killed at the National War Memoral in Ottawa yesterday was holding a ceremonial gun that was not loaded, according to reports.

"That is insane. For a cop or a soldier to carry a gun that doesn't work? ... He was a sitting duck," the judge argued.

(Below you can see the last photo taken of Cpl. Nathan Cirillo (left) before he was shot. It was snapped by a tourist.)

Watch the full discussion above.