If there was world war 3, which stocks should I short? With the Trump administration, Turkish dictatorship, North Korean nuclear weapons, and general tension around the world, we might think that there is a likelihood of something like a world war happening soon. If this were the case, and someone wished to profit from such a situation, which stock or commodities would be the best short (or invest in)?
Gold is generally the best option for expected political and economic strife as it generally reacts inversely with the markets. Here's a good article on the connection between war and the value of gold. 

Another thought would be to buy stock in companies involved in the defense industry. Raytheon, Boeing, Northorp Grumman all jump during wartime due to the anticipation for more demand for weapons production. 

An even safer bet would be to buy stocks in metal production such as steel given that in a wartime economy demand for these goods spikes as production of ships and vehicles will increase for a period of time.