A handful of homegrown terrorists “have exhibited improved tradecraft and operational security and increased willingness to consider less sophisticated attacks, which suggests the HVE threat may be evolving.”
During most of the past decade, most HVEs “did not have the technical capability to match their aspirations.” But in 2009, US-born “extremists” who were trained overseas attempted “two mass-casualty explosive attacks” on US soil.
As a result, intelligence officials “remain alert to potential dynamics” that could galvanize HVEs.
These include “a series of events perceived to reflect an anti-Islamic bias,” US military involvement in another Muslim country, and increased “HVE use of the Internet to share propaganda, form social or peer networks, or recruit others for attack planning.”