Sherrilyn Ifill is the president & director-counsel of the NAACP Legal Defense & Educational Fund Inc. The views expressed in this commentary are hers.

Within hours, Timothy Caughman, a black man from Queens, stumbled to a midtown police station bleeding. He had been stabbed , ultimately fatally, with a 26-inch sword. "What are you doing?" Caughman had asked his assailant.

James Harris Jackson gave police officers his answer : He hates black men and has since his youth. His plan was to kill more people than Caughman. He considered taking an officers' gun and shooting more black men.

The tragic killing of Timothy Caughman is a heinous hate crime. It is also an act of domestic terrorism. And it matters that we begin to name white supremacist murders in this way.

His crime bears eerie similarity to that of Dylann Roof , who committed mass murder in Emanuel AME Church in April 2015. Like Roof, Jackson chose the location for his alleged crime to heighten the public significance of his act. New York, Jackson told police, was ideal because it is the "media capital" of the country. Roof, who lived in North Carolina, chose Emanuel Baptist in Charleston, South Carolina, after he learned about the historic significance of the church. Jackson claims to have left a manifesto, like Roof, on his computer, which he says will "explain" his actions.

Crimes like these certainly seem to be acts of terrorism, but our federal terrorism law doesn't account for prosecution of true homegrown terrorism, that which comes from Americans, against Americans, and without foreign influence.

Of course, Dylann Roof was convicted of murder and is the first federal hate crime defendant sentenced to death in federal court, although many family members of his victims opposed the death penalty. And James Jackson has been charged with second-degree murder in New York and faces decades in prison. The District Attorney's Office has indicated it is considering classifying Jackson's alleged acts as terrorism under state law, which would make him eligible to be charged with first-degree murder, carrying the possibility of life in prison.

The terrorism designation is significant, not only because of the possible sentence. Even if he is convicted of second-degree murder, Jackson will be imprisoned for a very long time. The designation is significant because it properly recognizes the way in which African-American and other minority communities can be victims of white supremacist terrorism within the United States.

This failure to establish a federal penalty for domestic terrorism has historical roots as well.

Lynching -- the indiscriminate killing of (mostly) black people in the American South during the late 19th and 20th centuries by hanging, burning, dragging, drowning and shooting -- unleashed a wave of terror in African-American communities. The randomness and brutality of the violence was central to the way in which it spread terror. Black victims were lynched for any reason at all: failing to tip one's hat, insisting on repayment of a debt, false charges of rape or murder, and even being too prosperous.

The public nature of the crime was also deliberate. Lynchings were "message" crimes, designed not just to harm the individual but also to let all African-Americans in the community that they were not full citizens. Thus lynching, as with all forms of terrorism, differs from other violent crimes in that it is designed to intimidate particular groups and to use fear to make citizens complicit in limiting their own freedoms.

Throughout the first half of the 20th century, civil rights activists fought to pass a federal anti-lynching law. Those efforts were unsuccessful, a shameful history for which the United States Senate apologized in 2006 . State law enforcement and prosecutors almost never arrested or prosecuted lynchers -- certainly not for murder -- and thus the impunity with which perpetrators could commit these crimes became part of the terror as well.

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Understanding the ideological forces that promote violent extremism is essential to developing strategies to prevent future killers from carrying out their plans. In addition, properly designating white supremacist acts of terror could provide the proper law enforcement lens from which to investigate these cases.

Most of all, designating these crimes as terrorism sends a message to vulnerable communities that their fears are understood, and that violent white supremacy is recognized as a threat to American security as well as to individual victims.