The self-proclaimed caliphate has been reduced to a handful of villages in the Syrian desert, but the “virtual caliphate” fights on, a diminished but still formidable presence focused on rallying the group’s followers in the face of crushing military defeats, according to U.S. officials and independent analysts. “The depletion of ISIS on the battlefield has not yet translated into the degradation of ISIS in the online space,” said Tara Maller, a former CIA military analyst and senior policy adviser for the Counter Extremism Project, a nonpartisan group that promotes policies to block extremist content online. “What we see is a continuing effort to engage online and an increased effort to inspire people to carry out lone-wolf attacks.”