The QAnon movement’s evolution, from an Internet hodgepodge to a hallmark of pro-Trump violence, is a signal of the danger it poses to security this weekend and going into next week’s inauguration. It also presents long-term challenges for President-elect Joe Biden by fomenting resistance to democratic governance and to measures needed to corral the coronavirus pandemic, including mass vaccination.

“The takeaway from this is that disinformation is a threat to our democracy,” said Joel Finkelstein, co-founder of the Network Contagion Research Institute, a research group that studies online disinformation. “And we’re not nearly done.”

As much of the nation — including leading Republicans — expressed horror at last week’s events, a different narrative was playing out in the parallel online universe that has grown around Trump’s presidency and helped sustain it through perpetual upheaval. The siege was justified, described on Twitter by one QAnon devotee as “the least we can do.” Or it was staged as a false flag to discredit Trump supporters, with its participants as the true victims.