The Pentagon’s new plan to counter extremism within its ranks includes prohibitions on liking and sharing social media content that “endorses extremist activities,” which critics worry will have a chilling effect on speech. The Department of Defense (DoD) announced its counter-extremism policies Dec. 20, unveiling policies that are the result of a Counter Extremist Activity Working Group established in April by Defense Sec. Lloyd Austin. The plan doesn’t introduce any new concepts, instead updating an anti-extremism policy that’s existed since 1969 to account for social media and other developments. Among the changes include an update to the definition of “active participation” in extremist activities to include “posting, liking, sharing, re-tweeting, or otherwise distributing content—when such content is taken with the intent to promote or otherwise endorse extremist activities.” However, the DoD hasn’t clarified what exactly could constitute a violation of this rule. Pentagon press secretary John Kirby was tight-lipped about …