Nathaniel Rakich: A Big Blue Wave Could Overwhelm The GOP’s Advantage In The House: "A switch is thrown at D+8 that causes actual Democratic seat gain to go from behind their popular-vote gain pace to well ahead of it. So what happens at D+8? Republicans’ structural advantage in how districts are drawn (gerrymandering, as well as the phenomenon of self-sorting, whereby Democrats tend to cluster in cities, which are already heavily Democratic) begins to erode. That advantage normally allows Republicans to keep control of the House while still losing the popular vote by a modest margin. But if Republicans lose the popular vote by too much, their firewall might break all at once, and Democratic gains could multiply...