The grassroots Democratic organization Indivisible is launching its own team of stealth fact-checkers to push back against misinformation — an experiment in what it might look like to train up a political messaging infantry and send them out into the information trenches. Called the “Truth Brigade,” the corps of volunteers will learn best practices for countering popular misleading narratives on the right. Considering the scope of the misinformation that remains even after social media’s big January 6 cleanup, the project will certainly have its work cut out for i...