Will There Be A “Blue Wave” in 2018? Sure…Maybe…Perhaps Not

In the race to become the top prognosticator of this year’s midterm election, it is easy for many political observers to get ahead of themselves and make bold proclamations. The majority opinion appears to be that a “blue wave” is going to sweep the nation in response to Trump. It certainly could happen, but observers ought to be careful to not get too confident too early on. A healthy dose of skepticism is best when it comes to predictions about what will happen in November.

That certainly doesn’t mean that all opinions about whether Democrats will be successful in taking back Congress should be bluntly dismissed. But there is still plenty of time for things to change. The amount of time between now and Election Day can be an eternity in politics. Events that cannot be foreseen can and probably will happen.

So, is there going to be a “blue wave” in 2018? Are Democrats going to storm in and take a huge swath of state and federal offices away from Republicans? It is certainly within the realm of possibility, and they have a lot going for them this year. The aim of this article is to give a sense of what sort of data political commentators use for their respective analyses and how such data should be used. It isn’t comprehensive by any means, but some common themes emerge.

Midterms in General

In a historical context, the incumbent president’s party tends to do poorly in midterm elections.

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Source: Gerhard Peters. “Seats in Congress Gained/Lost by the President’s Party in Mid-Term Elections.” The American Presidency Project. Ed. John T. Woolley and Gerhard Peters. Santa Barbara, CA: University of California. 1999–2015. Available from the World Wide Web: http://www.presidency.ucsb.edu/data/mid-term_elections.php.

Since 1934, the incumbent president’s party has lost an average of 27 seats in the House and 4 in the U.S. Senate. Compare that to presidential election years below, where the president’s party has gained an average of about 14 seats in the House and about two in the Senate since 1932.

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Source: Gerhard Peters. “Seats in Congress Gained or Lost by the President’s Party in Presidential Election Years.” The American Presidency Project. Ed. John T. Woolley and Gerhard Peters. Santa Barbara, CA: University of California. 1999–2017. Available from the World Wide Web: http://www.presidency.ucsb.edu/data/presidential_elections_seats.php.

It is also sometimes cited that Republicans have a midterm turnout advantage. Midterms tend to see a whiter and older electorate come out to vote, which statistically tends to benefit the GOP. This effect, however, is significantly muted when a Republican is the incumbent president, as seen below.

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Source: Harry Enten, FiveThirtyEight, “Do Republicans Really Have A Big Turnout Advantage In Midterms?”, https://fivethirtyeight.com/features/do-republicans-really-have-a-big-turnout-advantage-in-midterms/

The midterm advantage goes to Democrats. It wouldn’t be unprecedented or out of the ordinary if Democrats took back at least one chamber, or even both. The manner in which they do it or how many seats they take might be, however.

National Generic Congressional Polls

Generic congressional ballot polling asks survey respondents whether they would vote for the Democrat or the Republican for Congress, but without giving specific names. The idea is to give a baseline for how named candidates are doing compared to their party labels. The ones you see in the news¹ are almost always national-level polls (meaning respondents from anywhere across the country can be polled), so we’ll stick with those here. As a general baseline for determining public opinion at large, these national generic congressional polls are fine. It gives an idea of what the national general public feels about the two parties in Congress.

But they are completely useless when trying to figure out who is actually going to win elections. Why? It is a national-level poll about races that are ultimately much more local. Let’s say that the latest poll shows Democrats at an advantage of +5 over Republicans. The opinion of the country then, is likely somewhere around there at that point in time. But it doesn’t help at all if you are trying to determine who will win the Senate race in Missouri because that poll is going to include a whole lot of people outside of that state. They can’t even vote in that specific election. The opinions of Missourians are not going to match that of the entire country. Democrats aren’t going to be at an advantage of +5 in every single congressional race. Each race is unique.

A lot of times, what is true about the national level of politics is often confused for what happens at the state level, even by those who are seasoned observers of politics. Congressional district seats are each voted on by their specific electorate. What matters at the national level won’t always matter at the state level, or it won’t matter to the same degree.

Trump Approval

It’s no secret that President Trump’s national job approval isn’t doing well. While it has been ticking upward or has been relatively positive in some states, nationwide it has been hovering around 40% approval for most of his tenure. This has led to some speculation that anti-Trump fervor will energize this Democrats to come out to vote.

The truth is that it is more complicated than that. Anti-Trump messaging will certainly appeal to most Democrats, but whether it will be enough to get them to come out and vote is up for debate. Some races will have issues and policies that are more important to voters than simply standing against the Trump administration. Some Republicans will be able to effectively distance themselves from party association with Trump. Some Democrats won’t be able to win even with a strong anti-Trump stance because too many other things are running against them.

Of course, low presidential approval does not bode well for Republicans. But it is very easy to read too much into that information. Tying Republicans to Trump through the party association will have varying levels of effectiveness.

Recent Special Elections

According to data from Ballotpedia, Democrats had a net gain of 11 state legislative seats in 2017 special elections². Below is their table showing 2018 partisan change in state legislatures (as of July 31st).

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Ballotpedia. “State Legislative Special Elections, 2018.” https://ballotpedia.org/State_legislative_special_elections,_2018

Some seats that Democrats won at both the state legislative and congressional levels were won handily by Trump in 2016, such as the special election in Pennsylvania’s 18th congressional district earlier this year. This certainly suggests a solid level of Democratic strength.

Still, one should be careful taking away too much from special elections. They often happen at far different dates than regular elections. The electorate that comes out is also far different than those who turn up to presidential and midterm elections, as each type of election has different levels of turnout. The same results might not happen for a regularly-scheduled election.

Which Seats Are Up for Election?

The U.S. House divide is 236–193 in favor of Republicans at the moment (some seats are vacant). While no easy task, it is certainly within the realm of reason that Democrats could take back a House majority.

The Senate, however, is perhaps more debatable. While the media focus is primarily on the slimmest of Republican majorities there, it is seemingly often forgotten that far more Democrats are up for election there than Republicans — 26 (including two independents, Bernie Sanders and Angus King, that caucus with Democrats) compared to nine, respectively. Ratings from the Cook Political Report, Larry Sabato’s Crystal Ball, and Inside Elections point to a partisan balance in the Senate that is up in the air.

Almost exactly the opposite is true, however, for gubernatorial seats: 26 up for election this year are held by Republicans, nine by Democrats, and one by an independent (Alaska). Based on sheer number alone, Republicans have more to lose here. But again, every race is different. Massachusetts and Maryland, for example, are blue states where Democrats significantly outnumber Republicans. Yet not only are both of their governors Republicans (Charlie Baker and Larry Hogan, respectively), but they are beloved by voters of both parties.

Turnout has spiked in many states’ primaries for DemocratsMore Democrats voted in Georgia, Idaho, Texas, and Pennsylvania compared to recent previous midterms, for example.⁴ Republican turnout in U.S. House primaries has also increased in some areas, although not as much as it has for the Democratic side.⁵ This has helped add fuel to the “blue wave” narrative.

How much of this rise in Democratic turnout is due to Trump, though, is not entirely clear. It is the easy answer, and it is undoubtedly playing some role. Yet there are also competitive, high-profile gubernatorial and U.S. Senate races which are contributing to the enthusiasm as well.


There is certainly reason for Democrats to feel optimistic about elections in November, and there is certainly room for concern from Republicans. All things considered, Democrats arguably have the momentum and have the most going for them. But there is plenty of time between now and Election Day, which means plenty of time for all sorts of events to happen to swing campaigns in either party’s favor. The resulting 2018 partisan balance is far from a foregone conclusion and will likely stay that way until November 6th. And even if there is a total flip of power between Democrats and Republicans in Congress, that isn’t necessarily going to be unusual.

  1. Real Clear Politics. “2018 Generic Congressional Vote.” https://www.realclearpolitics.com/epolls/other/2018_generic_congressional_vote-6185.html

Written by

Senior Page Editor - Sayfie Review, Assistant Staff Writer - Ballotpedia (my views do not express those of my employers), M.A. in Political Science

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