We would like you to assess the QUALITY of each of the following argument (discussing Gun Control) and determine if the argument is Valid or Invalid. A valid argument is clearly interpretable and either expresses an argument, or a premise or a conclusion that can be used in an argument for the topic of gun control. An invalid argument is a phrase that cannot be interpreted as an argument or not on the topic of gun control.

That would theoretically work except the fact that more knife murders may occur then and perhaps guns will be brought in illegally to murder people.
Valid

21 Most American gun owners are not violent criminals and will not be potential killers.
Valid

It's quite obvious by this and as well as the SCOTUS decision that the right to keep and bear arms is not dependent on the militia part, but the other way around.

Valid