His reluctance to use the word “terrorism” quickly became fodder for Donald Trump supporters to criticize Democrats for political correctness and weakness in taking on the country’s enemies. The Republican presidential nominee has criticized President Obama for avoiding the term “radical Islamic terrorism,” arguing that acknowledging the problem is the first step to combating it.

But determining whether an attack is terrorism can be far from simple.

Federal law defines terrorism as an intentional act that endangers life and is designed to coerce or intimidate the population, influence government policy or affect the conduct of the government. In other words, for an attack to qualify as terrorism, it has to be more than just terrifying. It requires a broader political motive.

By that definition, De Blasio had a point.