By Scott Walter, First Things - In 2013, George Zimmerman was acquitted of the charge of murdering Trayvon Martin, a black teenager. This was the spark that lit the Black Lives Matter movement (BLM). Three self-described “radical black organizers” responded: Alicia Garza coined the phrase in a “love letter” to black people, Patrisse Cullors turned the phrase into a hashtag, and Opal Tometi started organizing followers online and building BlackLivesMatter.com.