2018 Senate Election Scorecard

Click to enlargeby Gaius PubliusThe chart above represents my best guess about the future split of the Senate, using only races that seem contested. Note:• The Senate is currently divided 51-49 in favor of the Republicans, so the Democrats (and the two independents who caucus with them) are down two already.• The column labeled "Change 1" shows a best-case result for Democrats. The column labeled "Change 2" shows a worst case result based on my read of the possibilities and probabilities.The First Ten RacesRaces in the above chart are numbered 1 through 15. The first ten all have clear leaders. • Races 1–6 are all contests with Democratic incumbents where the Democrat is leading and expected to win, if only by single digits. Though there could be some surprises, they are not widely expected. Let's call those races for the Democrats. Net change: zero.• The next four races, numbered 7 through 10, are more in doubt. They feature two Democratic incumbents and two Republican incumbents. In all four, the Republican is leading. Though things could change, I expect a Republican winner in each of them.This means that Claire McCaskill and Heidi Heitkamp will lose, and Ted Cruz will keep his seat despite a strong challenge by Beto O'Roarke. Polls in the Texas race range from Tossup to Likely Republican, with Leans Republican the mean result, implying a mid-single-digit win for Cruz. We'll see.If the predictions for races 1–10 hold, Democrats have lost two seats already. Races Considered "Even"Let's treat the next six races, numbered 11 through 16, as three groups of pairs. All of these races are scored "even" by polling.• In the first pair of "even" races, the outcome is a little more predictable than the others. These feature two Democratic incumbents, Joe Donnelly (IN) and Joe Manchin (WV). If those outcomes are split — if Democrats win one and Republicans win the other — the Democrats lose another seat, for a net loss of –3.It appears now that Donnelly will lose and Manchin will win, so I'm counting these outcomes as likely in the best case column (Change 1) for a net no-change on the two races. In the worse case column (Change 2), both lose, and Democrats are now –4 seats so far.  • The second pair of "even" races are much harder to predict. These feature incumbents Democrat Nelson (FL), who's running against former governor Rick Scott, and Republican Dean Heller (NV), who's running against Democrat Jacky Rosen. If those two races are split, the composition of the Senate will depend on which way the split goes. The Change 1 column shows both Democrats winning, in which case Democrats pick up one seat (NV). In the worse case column, both Democrats lose, and Democrats are down –5 seats so far.I think it's slightly more likely that Heller will lose (Nevada is home to the Harry Reid machine) and that Scott will beat Nelson., so a middle outcome would have the two races split — Democrats taking NV and Republicans taking FL — for a net no change on the pair. • The final pair of races are for two open seats (AZ and TN), both of which were held by Republicans. I expect a split to be the most likely outcome, and if I had to guess, Democrats will win in Arizona with Kyrsten Sinema and Republicans will win in Tennessee.That's the best case; if so, Democrats pick up a seat from this pair. In the worst case, Republicans hold both seats, for a net of no change. SummaryIn the best case scenario (Change 1 column), the first ten races go as expected (for a loss of –2), and in the "even" races, Democrats lose Indiana but pick up Nevada and Arizona. The total change is a loss of one seat, and the new Senate is split 52-48 in favor of Republicans.In the worst case scenario (Change 2 column), the first ten races go as expected (for a loss of –2), and of the "even" races, Democrats lose all of them, for a total change of –5 seats. In that scenario, the new Senate split is 56-44.A middle case: The worst case scenario plays out, except that Sinema wins in AZ and Manchin wins in WV. That's still a net loss of three seats, and the new Senate is split 54-46.In all of these cases, Democrats lose ground in the Senate — in some of them quite a lot — and Chuck Schumer, I have to say, has presided over a failure, primarily because of his candidate selection and his dogged defense of people like Manchin, Heitkamp and Donnelly. The Bright SideDemocrats were never going to take the Senate anyway, not with this set of candidates doing what they've been doing.

Claire McCaskill is closing out the 2018 campaign with a call for "civility" and also immigrant-bashing caravan paranoia https://t.co/yCNmijWFul— Zach Carter (@zachdcarter) November 2, 2018

On the bright side, with this house-cleaning Democrats can build back up from a base set of senators that excludes Heitkamp, Donnelly, McCaskill, and maybe even Manchin and Sinema.GP