It's been in planning for awhile, but mostly the wait is for getting more workplaces in the US unionized to participate. Imo, we would need to convince key industries that could actually shut down the United States, it would be like: airline pilots/stewardesses, truck drivers, railroad workers, teachers, natural gas/electric workers, and health care workers. I don't know how progress is going, but even just 3 of those groups would be enough to cause a halt in what's, best case scenario, a more fragile administration.