As the World Economic Forum was drawing to a close on Saturday, local police used a water cannon against around 100 anti-capitalism protesters who had gathered at the Swiss ski resort of Davos. It was no doubt effective as a means of crowd control but it could hardly be described as "on message."

The incident came just days after a panel, including United Nations Secretary-General Ban Ki-moon, told delegates that the issue of water scarcity now poses one of the greatest threats to health, safety, economic growth, human rights...