Nate Cohn: “This was an electoral tsunami: a complete collapse of the Republican coalition and the largest victory by either party in half a century.”“When all the vote is in and counted, Democrats will win the national popular vote in all House races combined by 13 percentage points, according to our estimates. That would be the largest margin of victory since the post-Watergate elections in 1974 and 1976.”“And by one measure, it’s even larger: Democrats could flip as many as seven Senate seats that leaned Republican by more than 10 points in the previous presidential election.”“There’s simply no modern precedent for either party to do so well in states that had leaned so heavily toward the other side.”