The last two weeks have seen some significant movement in Democrats favor. First, there were the impressive results from last Tuesday’s elections. This week, we’ve seen two polls — one by Quinnipiac and one by Marist — that show Democrats with a congressional ballot advantage of +13 to +15. Three other recent polls — ABC/Washington Post, Fox, and NBC/Wall Street Journal — show Democrats with an advantage of anywhere from +7 to +15…

My colleague David Wasserman has been digging into the question of just how big of a wave Democrats need to get in order to surf into the majority. The short answer: they need to see a generic ballot advantage of +8 or more, which roughly translates to getting at least 54 percent or more of the national House vote in 2018.