When the 115th Congress took its first recess, members went home to their districts and in some cases to speak directly to their constituents via town halls. During recess members made news for one of two reasons: either they held a town hall which was packed with angry constituents or they opted not to hold an in-district event and were shamed by their constituents as a result.

Republican members who were targeted in particular complained bitterly about organized and so-called paid protesters. They were supported by the White House in their characterization. President Trump tweeted that the protests were “planned out by liberal activists” and White House Press Secretary Sean Spicer said that “there is a bit of professional protester, manufactured base in there.”

Despite accusations, town hall attendees aren’t being paid. They are however organized. And most of that organization comes from Indivisible, a guide to resisting the Trump Administration’s agenda, which in just a couple of months has taken the internet by storm. Here are four things campaigns and consultants need to know about Indivisible:

Indivisible began as a Google Doc As digital organizing goes the original Indivisible Guide was fairly low tech. Their current about page accurately describes it as a “poorly formatted, typo-filled Google Doc.” Essentially a brain dump of four ex-Democratic Hill staffers, the Indivisible Guide in its original form was intended as a way to help its authors share their knowledge of how Congress works, and cope with their own heartbreak over Trump’s win. It had no method for email capture, no digital ad buy behind it, and the document optimized for sharing. But The Indivisible Guide quickly found an audience desperate to oppose Trump and hungry for concrete actions they could take. Because it was the right tool in the right moment it spread like wildfire online.

Indivisible was inspired by the Tea Party If crowded, raucous, congressional town halls look familiar to you that’s because they are. The authors of the Indivisible Guide are all veterans of the Tea Party wave, experiencing it first hand as staffers for Democratic members of Congress. The guide makes no attempts to hide that the tactics outlined come right out of the Tea Party’s own playbook offering “a step-by-step guide for individuals, groups, and organizations looking to replicate the Tea Party’s success in getting Congress to listen to a small, vocal, dedicated group of constituents.” in its Introduction.

Indivisible is decentralized, hyperlocal, and growing The Indivisible guide has been downloaded over a million times and had over 10 million pageviews. More than 6,000 local Indivisible groups have formed. They’re organizing local actions in their community and sharing their stories through social media using the #Indivisible and #resist hashtags. Indivisible offers resources for chapters including a group leader toolkit, a guide to getting media ready, even suggestions for how to deal with potential right-wing sabotage.

Indivisible isn’t going away anytime soon. What began as a hastily written Google doc has grown into a movement. Its founders are forming a 501(c)4 organization, and more than 10,000 donations have come in online giving them a solid foundation and large grassroots donor list. An email sent to their members on Monday, reminded them to pace themselves because opposing the Trump Administration is a marathon not a sprint. “Your energy will be needed in the months ahead, so make sure that you’re taking time to reflect and recharge so that you can be in this for the long haul. Change doesn’t always happen quickly, but with all of us standing indivisible together, it will happen, and we will win.”

Political professionals can learn a lot from the success of The Indivisible Guide. No consultant would have advised them to launch in the way that they did, but their lack of polish wasn’t a hindrance. A clear call to action, released at the right moment and at the right time, was enough to light a spark and inspire tens of thousands of people to take action. Recess might be over but the 115th Congress hasn’t heard the last from Indivisible. They have only just begun to fight.

Melissa Ryan has spent more a decade leading digital campaigns for Democratic political campaigns, and progressive advocacy organizations. She is the author of Ctrl Alt Right Delete, a weekly newsletter.