PRESIDENTIAL COATTAILS: What Are They?


This is the first post in the series “Mercurial Nation”, which will look at the elements that make up the political climate (the ‘mood’ of the country) and how they will affect the 2020 House Race.

The first element, Presidential Coattails, is split into two parts. Part 1, below, looks into what coattails are, what causes them and why they are losing power. Part 2 will focus on the 2020 presidential race and what different candidate strategies and outcomes could mean for the House.


Even a blog explicitly not about the presidency can’t avoid the ruckus at the top of the ticket. Because presidential votes are highly determinative of down-ballot votes, understanding presidential elections is a prerequisite to understanding House elections. The messy, complex relationship can be tidied up with the idea of presidential coattails — “that the winning presidential candidate can sweep into office fellow party members in down-ballot races.”

THE DIRECT MODEL
In the mundanely named “Direct Model of Coattail Effect”, a voter’s downballot decision process starts with their presidential vote.

Excluding local race dynamics, a House candidate’s baseline support in their district — measured by popular vote percentage — would match that of their party’s presidential candidate. A popular House candidate and favorable local dynamics will lift this percentage up; an unpopular House candidate and unfavorable local dynamics will drag it down.

House candidates that win, but with a smaller percentage of the district vote than their party’s presidential candidate — and who therefore benefited from the president’s higher level of support — are riding the president’s coattails.

The Direct Model is1In my opinion the clearest, most useful way to think about downballot candidate selection. The rest of the analysis rests on this model. 2So come at me if you think The Simultaneous Determination Model is more accurate.

To walk through an example of the candidate selection process, meet Sandra in the footnote->3Sandra lives in Moorhead, Minnesota (where they’re a bit overly excited about being the birthplace of the DQ “Dilly Bar”) and pays peripheral attention to the news. She is a strong supporter of the Republican presidential candidate because:

1) She’s a registered Republican.

2) She just got a pay raise.

3) She is pro-life.

So, Sandra goes and votes for the Republican presidential candidate. But what about those downballot races?

Sandra came to support the president and doesn’t know much about these other candidates. She decides to vote the Republican ticket all the way down to support her presidential pick and the Republican Party.

This is a presidential coattail vote — a downballot vote that comes from support for a presidential candidate.

In another world, Sandra still lives in Moorhead (and is just as proud of the ice-cream-on-a-stick heritage) but has seen ads saying that the Democratic House candidate supports the President’s economic agenda and is pro-life (Moorhead, Minnesota actually is in one of four districts represented by a pro-life Democrat) — both things that Sandra likes! Sandra also likes that the Democrat, Colin Peterson, used to be — and this is true— in a congressional bipartisan conservative rock/country/country rock band named “The Second Amendments”. 

In this world, Sandra splits her vote: Republican for President, Democrat for House. Thus (I’m allowed a pretentious word here and there) no presidential coattails.

THE POWER OF COATTAILS TODAY
How powerful are presidential coattails4From here on, referred to as just ‘coattails’. and are they getting stronger or weaker? Well, it’s complicated.

Coattails are measured by tallying the number of districts where the president’s vote total was greater than that of their party’s House candidate. By this measure, coattails are weak.

WHAT ARE COATTAILS MADE OF?
To understand why they appear to be weakening, we’ll look at the two pieces that determine coattail length: Presidential Popular Vote Percentage (PPVP) and Ticket Splitting Rate.

Presidential Popular Vote Percentage (PPVP)
The downward trend in PPVP is clear. Looking at the chart below, no presidential candidate has cracked 55% since Reagan in 1984.  It is also clear that the candidates who won in landslides — Eisenhower (1956), Johnson (1964), Nixon (1972) and Reagan (1984) — had the longest coattails.

So why are landslide elections and high PPVPs becoming less common?

Historically unpopular candidates… 

5Data from Gallup; Data Missing for 1988, 1996, 2000

and parties…

along with a stubbornly divided electorate with intense party loyalty.6There are plenty of analyses on the other factors that influence presidential elections. But what matters here is identifying the causes of the downward trend in PPVP. Everything else that is happening under the surface can stay there.

This environment limits a candidate’s ability to win over enough voters to reach into the mid-fifties, let alone garner enough votes for a landslide. And even recent elections with excited voters and high turnout— like Obama’s 2008 election — still feature a polarized electorate, and PPVPs around 50%.

Recent candidates, with their record unpopularity, have also boosted support for third parties. Third party votes have been on the uptick since 2004 and jumped in 2016. According to the 2016 exit polls, five percent of third party presidential voters7Voters who said they did not vote for Clinton or Trump or gave no answer. supported a Republican or Democrat House candidate. When seats are decided by one or two percent, the direction that these voters swing downballot can be decisive.

8Data from Dave Leip’s Atlas of U.S.

Ticket Splitting
A voter who supports candidates from different political parties on the same ballot is called a ticket-splitter. Their ballot is dubbed a split-ticket.

A popular House candidate with favorable local dynamics may pull enough votes to win a race in a district that their party’s presidential candidate lost. Likewise, an unpopular candidate with unfavorable local dynamics may lose in a district that their party’s presidential candidate won. These split-ticket districts can be one-offs, but if a national party does an exceptionally good or bad job with candidate recruitment9*cough* Democrats in 2010 *cough* or fundraising, it could have an aggregate effect.

It might seem that weakened coattails would mean a rise in ticket splitting. That’s not the case; split-ticket voting is at a record low. Take a look at this Washington Post graphic. It shows that ticket splitting on a district level has plummeted, particularly since 2012. Here is another picture showing the same trend.10Since I know some of you lazy boobs didn’t click the link.

The dive in ticket splitting has continued even as states do away with Straight Ticket Voting — the option to check one box and vote for all candidates of a single party.11Only 8 states will have the option in 2020. Given the antipathy between Republicans and Democrats, they’ll surely take the time to check those boxes D or R top to bottom.

The party loyalty trickles down from presidential politics into Senate, House, Gubernatorial, and even state assembly races. When it comes to elections of all levels, people take their cue from national party. This might be due to the nationalization of media or because national parties are a good and easy stand-ins for voters’ values. It’s a rabbit hole that goes down deep enough for books to be written on the subject.    

BRINGING IT ALL TOGETHER
Reading material that dense might be throwing spaghetti on the wall. If you need a summary, click the footnote –>12Presidential coattails are a factor of 1) Presidential Popular Vote Percentage (PPVP) 2) The percentage of their voters who split tickets downballot.

PPVPs have steadily decreased in recent years — a result of unpopular parties, unpopular candidates and high party loyalty — lowering the number of districts in which presidential candidates run ahead of the House candidate, which is one way to measure coattails.

Ticket splitting has fallen in recent years due to high partisan loyalty and the nationalization of politics and media.

So…are presidential coattails getting stronger or weaker?

It depends how they are measured. While presidential votes have become more and more indicative of House votes13Measured by falling ticket-splitting rates., low PPVPs are rarely enough to pull House candidates over the finish line.

Remember, however, that these trends are not destiny — they could intensify, reverse or hold steady. We live in a volatile and Mercurial Nation. Voters happy with the economy could view incumbents charitably, keeping Trump and a Democratic House. Voters could go to the ballot with hopes of electing a split government as a check on the parties, a theory known as balancing. Or voters could be hungry for change and elect a Democratic President and Republican House.

Next week we’ll go deeper into how the 2020 presidential election could play out and what these scenarios would mean for the House.

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