Given the Target and Argument texts detect the stance that the argument has towards the topic. There are three types of stances "in favor", "against", and "neutral". 

Topic: Libertarianism
 Argument: Free-market economics is the ideal form of (non)governance.
in favor

Topic: Natural gas
 Argument: Natural gas vehicles reduce emissions, fight global warming.
in favor

Topic: Legalization of Marijuana
 Argument: If marijuana is harmful, isn't this sufficient punishment for users.

in favor