Obama easily won Wisconsin twice, and his campaign built an organization that was based on neighborhood organizing, local volunteers and personal relationships.
It worked so well for Obama that Republicans in Wisconsin are trying to do it, too. At the core of this strategy is engaging voters early, where they live.
Many Democrats say Hillary Clinton's 2016 presidential campaign relied too heavily on ads and paid canvassers, and they believe their weak neighborhood network helped allow Trump to flip Rust Belt states Republican.
So Democrats are trying a block-by-block rebuilding of the infrastructure they let crumble.