You hear it all the time: The 2018 Senate map is bad, even “brutal,” for Democrats. Of the 35 seats on the ballot this cycle, 26 are held by senators who caucus with the Democrats, and just nine are held by Republicans. Democrats must flip two of those nine — without losing any seats of their own — in order to take a Senate majority. That’s not going to be easy given that only one of those Republican-held seats is from a state carried by Hillary Clinton in 2016. At the same time, 10 Democratic incumbents are running for re-election in states won by President Trump, including deep red ones like North Dakota and West Virginia.
But while the 2018 map is the party’s steepest uphill climb in a long time, defending red-state Senate seats isn’t a new challenge for Democrats. In fact, they’ve gotten pretty good at it over the years. They haven’t had a choice: It gets less ink than the gerrymandered districts in the U.S. House, but the Senate — which reserves the same number of seats for a sparsely populated state as for a crowded one — has an inherent Republican bias as well. Within the past 25 years, Democratic majorities in the Senate — up through 1995, briefly from 2001 to 2002 and then finally from 2007 to 2015 — were possible because more Democrats represented red states than Republicans represented blue states. To wield a majority in 2019 and beyond, Democrats will simply (OK, not so simply) have to pull off the same trick.
To quantify how well Democrats have overcome this handicap in the past, we calculated the historical FiveThirtyEight partisan leans1 of every state in every Senate map since 1992.2 Then, for each Senate election cycle, we looked at how many seats each party held going into the election as well as how many seats each party won coming out of the election.3 Here’s what we found….
They also had this….
….Sen. Claire McCaskill of Missouri has survived the growing Republicanismof her state by being good at politics. But she’s also been a bit lucky. And that combination may save her again this November.
McCaskill is not just politically endangered because she, along with nine other Senate Democrats, is running in a red state. President Trump won Missouri by 19 percentage points. But lucky for McCaskill, 2018 is not 2016. Trump is unpopular nationally — and his numbers have dipped in Missouri too….
Ironically, in the 1890’s (where the electoral map was essentially a reverse-image from the 1960s’), the equal representation of sparsely-populated rural farming, logging and mining states in the South, Plains and inland West (what are now the Red Heartland) favored the Democrats, while the Republicans (whom one could argue were no more conservative than their Democratic contemporaries) could only send two Senators each from densely-populated industrial and commercial states in the Northeast and around the Great Lakes (e.g. Massachusetts, Pennsylvania, Ohio, Illinois), states which have (between say 1980 and 2012) been the Blue bastions.