Will Retirements Further Reduce the GOP’s Ranks?

I have written a couple of articles here about the net difference by party in the number of Representatives retiring from the House. I found a relatively strong relationship between retirements and the number of seats won or loss in off-year elections, but I found no relationship between the two measures in Presidential years.

These two charts tell the basic story. On the left we have the relationship for off-year elections, where changes in the number of Republican retirements correlate with the number of House seats won or lost in each election. The chart on the right presents the same measures for Presidential years. In off-year elections, the number of Republican seats won or lost depends to a degree on the difference between the number of Republicans and Democrats retiring from the House. In years like 1958 and 2018, relatively large numbers of Republicans left the House, and the party lost seats overall.


The chart on the right shows there was no systematic relationship between retirements and House results in election years dating back to 1936 when the President is on the ballot. However before we jump to the conclusion that retirements will again not be predictive in 2020, a closer look is in order.

This year 28 Republicans (counting Justin Amash) have relinquished their seats in the House of Representatives compared to nine Democrats. This difference of +19 in net Republican retirements is the second-largest number recorded for an on-year election since the New Deal, just behind the value for 2008. In that year there were 21 net Republican retirements, and the party lost 24 seats. Only the 1964 landslide election between Johnson and Goldwater saw more Republican seat losses.  Might the 2008 result be a bellwether for the result in 2020?

Using the ratings at the Cook Political Report we find two open seats in the “likely Republican” category, three in the “lean Republican” category, and five more seats considered Republican “toss-ups.” For the Democrats, two open seats fall into the “likely Democratic” category, one in the “lean Democratic” group, and just one more is considered a toss-up. Overall we have eight Republican seats in the lean/toss-up categories compared to just two Democrats.

Having as many as 19 retirements from the President’s party in a year when he is running for re-election is extremely rare. Since 1948, net retirements in years when the President is on the ballot averaged just 3.6 (both Democrats and Republicans), reaching a maximum of seven in 1996. That makes it difficult to evaluate the meaning of this year’s net departure of nineteen Republicans.  Perhaps we may not see a “blue wave” result like 2008, with its 21 net Republican retirements and a net loss of 24 GOP seats. But it wouldn’t be surprising to see the Democrats pick up some eight to ten House seats in November.

Retirements as a Bellwether for House Elections

There have been eleven midterm elections when House retirements by one party outnumbered those of the other party by six or more seats.  In all but one election the party with the greater number of retirements lost seats.


In the months before the 2018 election forty Republican House Members chose to give up their seats rather than pursue re-election, by far the greatest Republican exodus since the New Deal. The previous Republican record of twenty-seven was set in 1958 during the Eisenhower recession. Democrats once saw forty-one of their Members choose to depart the House in 1992 when Clinton was first elected.

However it is not the volume of a party’s retirements that matter as much as the excess of retirements from one side of the aisle or the other.  To be sure, Members of Congress retire for many reasons. Age and illness catch up with the best of us.  Some Members give up their House seats to seek higher office like Kyrsten Sinema and Beto O’Rourke did this year.

Still, Members also pay close attention to the winds of politics for fear they might be swept out of their seats. Some choose to retire rather than face an embarrassing defeat in the next election.  Such “strategic retirements” might prove a plausible bellwether for future elections.  If many more Members of one party are leaving their seats than the other, that might bode ill for the party’s results at the next election.

One thing is certain, retirements prove useless for predicting House results in Presidential election years.  Presidential politics overwhelms any effect we might see for strategic retirements in House elections.

The picture looks different in midterm elections.  Years that saw more Republicans retiring compared to Democrats were also years where more seats swung from Republican to Democratic hands.  This past election joins 1958 as years when an excess of Republican departures from the House foretold a substantial loss of seats at the next election.

The horizontal axis measures the difference between the number of Republican Members who left the House before an election and the number of Democrats who gave up their seats.* The vertical axis shows the swing in House seats compared to the past election. For instance, in 2018 forty Republicans and eighteen Democrats left the House, for a net retirements figure of +22 Republican. The “blue wave” swung forty seats from the Republicans to the Democrats, about nine fewer than the best-fit line would predict.

Some readers might ask whether that nine-seat deficit reflected Republican gerrymandering in the years since the 2010 Census.  I simply cannot say.  The likely error range (the “95% confidence interval”) around the prediction for any individual year averages about a hundred seats.** With that much variability, detecting things like gerrymandering effects is simply impossible.

As a bellwether, then, retirements seem pretty useless.  They appear to have so much intrinsic variability that any effects of strategic decision-making by Members remain hidden.  Suppose we group elections by the difference in retirements.  Will we see any stronger relationship with the election result than we have so far?

In the six elections where the number of retiring Republicans outnumbered retiring Democrats by six or more Members, the Republicans lost seats in five or them.  The same held true for elections when six of more Democrats retired compared to their Republican colleagues.  The Republicans gained seats in all five of those elections.

So retirements can prove a useful predictor of future election results if we limit our attention to the more extreme years where one party’s retirements outnumber the other by six or more.  The party with the excess of retirements has lost ten of the eleven elections fought in such circumstances.

 

 

*The data on Congressional retirements come from the Brookings Institution’s invaluable Vital Statistics on Congress.  The figure for 2018 come from the New York Times.

**The height of the bars depends on the overall “standard error of estimate,” in this case 23.8 seats, the size of the sample (21 elections), and the difference between the number of retirements in a given year and the mean for all years.  The confidence intervals average about plus or minus fifty seats for any given election.

Republicans Continue to Leave the House

Three more Republican House Members announced they would not seek re-election this week, bringing the total number of retiring Republican Members to 34 according to the New York Times. That figure compares to 16 Democrats, for a net Republican difference of +18.  We have to look back to the Democratic landslide in 1958 to see a mid-term with double-digit net Republican retirements.  For Democrats, only in 1938 and 1978 did the number of their retirements exceed Republican retirements by ten or more.

This increase of three net Republican retirements raises the predicted Democratic seat swing to 41 using the relationship depicted in the previous article.

I have shown in earlier postings that the relationship between seats and votes that advantaged Democrats in the years after World War II moved steadily in the Republicans’ direction beginning in 1980 and, with the help of gerrymandering, became even more favorable for the Republicans after 2010.  That might temper our belief in a prediction for an election being held in 2018.  First, the 2018 retirement margin of -18 is close to the observed maximum of -21 in 1958.  Perhaps the 1958 election is an “outlier” and without it the relationship is less steep than we observe.  However slope and intercept coefficients estimated with 1958 excluded are numerically nearly identical to those estimated with that year included.  So it’s unlikely that the historical model is radically overestimating the likely result next fall.

Another test is to let the relationship differ before and after 1992 to see whether the structural changes that we observe in the seats/votes relationship in the current era appear in the relationship for retirements and seat swings.  Once again, allowing the coefficients to differ before and after 1992 showed no measurable statistical difference. While the effects of gerrymandering and partisan self-segregation may make the House less vulnerable to “waves” of Democratic support, there is no evidence for that thesis looking at retirements as a predictor of seat outcomes.

These estimates have a lot of uncertainty attached.  The standard error of estimate is about 28 seats.  That means there is about a two-thirds chance that the actual swing will be somewhere between 13 and 67 seats.  Since the Democrats need a swing of at least 24 seats to win control of the House, even a retirement margin of 18 is not enough to ensure a change in party control.

The regression model taking President’s partisanship into account is a bit more conservative; it predicts a swing of 37 seats.

Update (2/26/18) – One more Republican has announced he is leaving the House, along with one more Democrat.  The net difference remains at +18.

What Do House Retirements Tell Us About the Future?

The pace of Republican retirements predicts that Democrats should take back control of the House of Representatives this fall by a margin of eight or nine seats.

This week Edward Royce (R-CA), Chair of the House Foreign Affairs Committee, and Darrell Issa (R-CA), former Chair of House Oversight and Reform, joined 27 of their fellow House Republicans by announcing that they are retiring from the chamber.  About half are leaving public office entirely, while the remainder are seeking another office like governor or senator.  (Issa has threatened to run for the House again in an adjacent district.)

On the other side of the aisle, fourteen Democrats have announced that they will be leaving the House of Representatives.  Only five of them are leaving public office, though Ruben Kihuen (D-NV) may be joining them subject to an investigation into allegations of sexual harassment.

Many pundits have interpreted the much higher retirement rate for Republicans to be a bellwether for this fall’s Congressional election.  If no one else announces a retirement, the Republicans will face a net loss of fifteen seats going into the midterms.  Just how large a threat do such retirements pose to Republican control of the House?

These two charts show the relationship between the net Republican margin of victory in terms of seats in the House and the net partisan difference in retirements.  It turns out that retirements tell us essentially nothing about Congressional outcomes in Presidential years, but they are quite informative in mid-term elections like 2018.  Here is the chart for Presidential years:

In presidential years we see little relationship between net Republican retirements and how well the party fares in the upcoming general election. What matters more are Presidential “coattails” with Republican swings in years when Eisenhower (1952), Nixon (1960, 1972), and Reagan (1980) ran.  Democrats were favored when they ran along side Johnson in 1964, Obama in 2008, and Franklin Roosevelt in 1944.

A much different picture appears if we look at the same relationship for mid-term years.

Now the number of Republican seats won or lost depends much more directly on the number of retirements.  The line is anchored by the Republicans’ success in the 1938 midterm and their dramatic losses in the 1958 election. If the figure for net retirements remains at fifteen, the Republicans are predicted to lose about thirty-two seats next November.  That would give the Democrats control of the House with a margin of eight seats.

However, because the President’s party historically loses seats in midterms, we should expect to see more retirements from the President’s party in midterm years.  When Democrats presided over a midterm, an average of four more Democrats retired from office than did Republicans.  When the Republicans held the White House in a midterm year, retirements from their ranks outnumbered Democratic retirements by an average of six.

So some of the strong relationship we see between retirements and midterm losses arises simply because the President’s co-partisans are jumping ship knowing that their party will do more poorly in the upcoming midterm.  That leaves us with the question of whether retirements have any additional predictive power once we take the President’s partisanship into account.  Retirements still matter in this better specification, though that effect just achieves statistical significance.


Based on these estimates, in a year where the Democrats hold the White House, and the number of retirements on both sides of the aisle is equal, the model predicts that the Republicans should gain about thirty seats.  When the Republicans hold the White House, and retirements are equal, the Democrats should gain about twelve seats (= 30.2 – 42.1 = -11.9).  Regardless of which party controls the Presidency,* Republicans are predicted to lose 1.4 seats for every retirement.  Applied to the current circumstances, this formula predicts a Democratic victory by thirty-three seats, or one more than predicted by the simpler model.

 

 

*Allowing the relationship between retirements and seat outcomes to vary separately depending on which party controlled the White House added no explanatory power.