From the Introduction: "This National Strategy for Countering Domestic Terrorism provides an overarching approach to address today's manifestation of the domestic terrorism threat as well as the evolving forms that the threat may take in the years ahead. [...] This Strategy is organized around four pillars - the core elements of how the U.S. Government will tackle the threat posed by domestic terrorism today. First are efforts to understand and share information regarding the full range of domestic terrorism threats. Second are efforts to prevent domestic terrorists from successfully recruiting, inciting, and mobilizing Americans to violence. Third are efforts to deter and disrupt domestic terrorist activity before it yields violence. Finally, the long-term issues that contribute to domestic terrorism in our country must be addressed to ensure that this threat diminishes over generations to come. [...] All told, today's domestic terrorism threat poses a danger to Americans, our democratic society, and our national security that we must counter aggressively, comprehensively, and responsibly. Doing so will make America not just safer, but also stronger - and more unified. What follows is America's first government-wide national Strategy to do so."
White House: https://www.whitehouse.gov/