How Tesla Takedown got its start

On a sunny April afternoon in Seattle, around 40 activists gathered at the Pine Box, a beer and pizza bar in the sometimes scruffy Capitol Hill neighborhood. The group had reserved a side room attached to the outside patio; before remarks began, attendees flowed in and out, enjoying the warm day. Someone set up a sound system. Then the activists settled in, straining their ears as the streamed call crackled through less-than-perfect speakers.

In more than a decade of climate organizing...