Complex sentence: The Nazi gun control argument is a counterfactual history proposal that gun laws in Nazi Germany were a significant component of the Third Reich's plan, and that victims, especially Jews, might have more effectively resisted repression if they had been armed or better armed.
Split into simpler sentences: The Nazi gun control argument is a counterfactual history that proposes a connection between gun laws in Nazi Germany and the inability to effectively resist repression. The argument suggests that victims, especially Jews, could have more effectively resisted if they had been armed or better armed.