The massacre of 49 people at a gay nightclub Sunday in Orlando, Florida, sparked a war of words over how to describe it.
Presumptive Republican presidential nominee Donald Trump was quick to seize on the shooter's ethnicity — incorrectly calling the U.S.-born perpetrator an "Afghan" and describing the attack as an act of "radical Islamic terrorism."
Earlier this week, Trump taunted presumptive Democratic presidential nominee Hillary Clinton and President Barack Obama for not using the terms. Obama argued against using labels. Clinton said she would not avoid calling it "radical Islamism."
Why are the words important? Let's try to define the ones involved.
"Islam" is straightforward. It's the religion of 1.6 billion people.
"Islamic" is the adjectival form of the word, often used to describe religious art, texts and architecture.
"Islamism" is a religious, fundamentalist, political ideology, with practitioners as varied as the Muslim Brotherhood in Egypt and the ruling elite of the Shi'ite-dominated Islamic Republic of Iran.
In the United States, in the era of the Islamic State group and al-Qaida, the term "radical Islamist" is usually used to describe advocates of the violent strand of ideology linked to the Wahhabi and Salafi fundamentalist Sunni schools of Islam.
"Radical" can be defined as "outside the mainstream." Killing people for being gay is so far outside the mainstream in the United States that it is not just a crime, it falls into a category for especially heinous acts — a hate crime.
Not so elsewhere, where the punishment for homosexuality can be death. The Washington Post this week identified 10 countries where that is the law of the land, including U.S. allies Afghanistan, Saudi Arabia, Qatar and the United Arab Emirates.
What about 'terrorism'?
If radical is relative, so too is the word "terrorism." When applied to recent mass shootings in the U.S., mainstream media overwhelmingly refer to killers who invoke Islamic State as terrorists. The term becomes more contentious when applied to other killers, such as those who support white supremacy or oppose abortion on biblical terms.
It's not clear exactly what Trump means by "radical Islam," but he uses it often, most recently to justify his proposed temporary ban on Muslims entering the country.
And he insists that Obama use some form of the word "Islam" to describe the violence that took 49 lives Sunday. Within hours of the shooting, Trump tweeted, "Is President Obama going to finally mention the words radical Islamic terrorism? If he doesn't, he should immediately resign in disgrace!"
“Calling a threat by a different name does not make it go away," the president said the next day. "This is a political distraction. Since before I was president, I have been clear about how extremist groups have perverted Islam to justify terrorism."
And, he has argued, to keep from tainting a whole religion with the actions of a few, he has avoided the phrase ever since.