The Collapse of the Voting Structure — Possible Big Trouble Ahead

Donald Trump will be sworn in as President of the United States next Friday, 20 January 2017. This surprised most analysts including ourselves! We expected to be writing posts during 2017 about splits in the Republican Party due to President Hillary Clinton’s pressing a legislative program that would have been attractive to enough Republicans to have caused serious conflict in the Republican caucuses. Instead we have a President who is both a real estate tycoon and a television entertainer. What his policy views are in many areas are opaque (to say the least).

What we find alarming is the unprecedented collapse of the long-term structure of Congressional Voting during the past 20 years. Contrary to what many scholars say when they cite our book, Congress: A Political-Economic History of Roll Call Voting (1997, New York: Oxford University Press), Poole and Rosenthal DO NOT CLAIM that voting in Congress is largely one-dimensional. Rather Poole and Rosenthal show that a two-dimensional dynamic spatial model is the best fitting model for Congresses 1 – 99.

What has happened in the past 20 years is that the second dimension of Congressional voting has slowly evaporated. As late as the 1990s the second dimension picked up differences within each of the parties over abortion, gun rights, and other social or lifestyle issues. For example, on the vexed issue of abortion each Party had a pro-choice and a pro-life faction. Hence, roll call votes on Abortion often cut through the parties along the second dimension. The same was true for gun control (see the spatial maps in this post). Hare and Poole show the second dimension disappearing in a variety of issue areas in this analysis.

The two figures below show that the extraordinary divisiveness that has marked American Politics since November 2000 has resulted in Congressional voting to collapse into a one dimensional near Parliamentary voting structure; that is, the parties are very unified as shown by Party Unity Scores. The first graph shows the correct classification for each House in 10, 2, and 1 dimensions using Optimal Classification. Note the dramatic convergence of all three measures during the past 20 years. This shows that almost every issue is voted along “liberal-conservative” (it is hard to make sense what this dimension means any more!) lines. Furthermore, no other period in American history shows this pattern.

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This graph shows the Aggregate Proportional Reduction in Error (APRE) ([{Minority Vote on a RC – Classification Error}/Minority Vote on a RC], summed over all the scaled roll calls). The APRE controls for the margins of the roll calls. The same pattern of collapse is shown here as well.

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Donald Trump will be the third consecutive President who is widely disliked by members of the opposite Party. Indeed, Trump’s personality coupled with the extraordinary party unity within each party will mean that American Politics will enter a phase that has never been seen before. We hope things do not melt down but we would not bet our mortgages on it!

The End of the 114th Congress

The 114th Congress has finally ended. The most polarized Congress since the early 20th Century and one where almost all issues have been drawn into the first dimension [we will address dimensionality in a future post; the current period is unique in American history].

In our last post cited above, we, like most other election watchers, assumed that Secretary Clinton was on a path to a certain victory over Donald Trump. This post would have dealt with what we anticipated to be certain splits within the Republican caucus of the House (we expected the Senate to be 50-50 or 49-51 in favor of the Democrats). All that has changed.

However, it is hard to see how some of President-Elect Trump’s policy positions can be reconciled with the views of the Republican Caucus in either Chamber. For example, in this blog post by Sam Quinones he discusses how the opioid epidemic is correlated with Donald Trump’s Performance in the Election [the analysis in the linked PDF is by Shannon Monnat of Penn State University]. As Quinones notes, these areas that strongly supported Trump will require “massive investment in drug treatment before they can be great again.” We called attention to Quinones’ work in a post early this year and in this op-ed by CDC Chief Thomas Friedman he discusses the seriousness of this epidemic.

Below is a smoothed histogram of the 114th House and Senate using our Constant Space DW-NOMINATE Scores. Note the gap between McConnell (R-KY) and Ryan (R-WI) and the gap between Pelosi (D-CA) and Schumer (D-NY). Add in the filibuster requirement of 60 votes on legislation and it is hard to see how Trump can pass meaningful social policy to help those areas that strongly supported him. Trump may be more successful with taxes and deregulation that would help his supporters but that remains to be seen. The 115th Congress will not be boring.

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House and Senate Means 1879 – 2016 (as of October 2016)

Revised 18 November 2016
ANNOUNCEMENT — Jeff Lewis of UCLA will be taking over the 34 year long NOMINATE project from Keith Poole and Howard Rosenthal effective at the end of this year. At that time this Blog and will go to a new website at UCLA that will also incorporate the old Voteview-For-Windows Software. The website will be up until early 2018 to archive all of the data and unpublished papers/Monte Carlo studies done by Poole and Rosenthal in the past 34 years. We will post a notice on the PolMeth mail server as well as other outlets announcing the exact timing of the switch over. Poole and Rosenthal will be happy to answer questions but inquiries as of 2017 should be directed to Jeff Lewis and his outstanding group of programmers.

The 114th Congress will pass into history in two months. Before it does there will be a lame duck session that, with Hillary Clinton’s almost certain victory [WHOA — Did we call that one wrong!!!] and Republican losses in both chambers, will likely wrap up in a matter of weeks. The small number of roll calls will not change the figures below that much.

Below we show the polarization series for the House and Senate using the Weekly CS DW-NOMINATE scores. The impact of the last three elections — 2010, 2012, and 2014 — on the Republican Party seems to have been the large influx of “Ted Cruz” Republicans. Polarization has jumped sharply from the first two years of President Obama’s first term. Polarization in the House may have leveled off (see below) but the Senate increase is much larger than the House.

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The figures below show the means of the two parties in each Chamber on both dimensions over time. The House Republicans actually moderated very slightly in the 114th while the House Democrats show absolutely no difference between North and South and the two have converged. The slight uptick in polarization in the House is due to the leftward movement of the Democrats being slightly greater than the leftward movement of the Republicans.

The Senate for the most part tracks the House on the first dimension. The main difference is that there are still three Senators from the South (the eleven states of the Confederacy plus Kentucky and Oklahoma [CQ’s definition]). Those three [Nelson (D-FL), Kaine (D-VA) [who will be Vice President in January], and Warner (D-VA)] are more moderate than their Northern counterparts. Nonetheless, the Senate Democrats are moving to the left and the Senate Republicans are moving to the right thereby increasing polarization in the Senate at a faster rate than in the House.

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The Second Dimension at one time picked up conflict over Civil Rights for African Americans but, beginning in the early 1970s until the early 2000s “Social Issues” such as abortion and gun control (see Poole and Rosenthal, 1997; McCarty, Poole, and Rosenthal, February 2016). The Second Dimension has faded to insignificance but could make a come back with a possible split in the Republican Party during the 2016 elections.

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The Presidential Square Wave Through the 113th Congress

Below we plot the first dimension DW-NOMINATE Common Space scores of the presidents in the post-war period, which we refer to as the “presidential square wave” due to its shape. An ideological score is estimated for each president throughout the entirety of their tenure in office by scaling their “votes” on a subset of roll calls on which they announce a position (measured using CQ Presidential Support Votes). Negative CS DW-NOMINATE scores indicate greater liberalism and positive scores indicate greater conservatism. The presidential scores are directly comparable across time and with members of Congress. However, there was a significant second dimension dealing with Civil Rights that lasted into the early 1990s. This will affect the first dimension scores of Presidents prior to George H. W. Bush.

These presidential CS DW-NOMINATE scores are estimated using all available CQ presidential support roll calls through 2015.

Very little has changed from the last presidential square wave. President Obama fits the spatial model estimated by CS DW-NOMINATE extremely well, with over 95% of his 803 “votes” correctly classified. Obama has moved very slightly rightward (-0.354) and is now just to the left of LBJ (-0.337) and right of Truman (-0.373), though this trio is virtually ideologically indistinguishable. President Eisenhower is the most moderate president (0.282) of the post-war era.

Among members of the 113th Congress, President Obama is very ideologically close to Representatives Stephen Lynch (D-MA) [-0.355] and Marcy Kaptur (D-OH) [-0.352] in the House, and Senators Charles Schumer (D-NY) [-0.350] and Mark Udall (D-CO) [-0.353] in the Senate.

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Law and Order in the 2016 Election

Below we show voters’ feeling thermometer ratings of the police and Black Lives Matter (BLM) using data from the 2015 Cooperative Congressional Election Study. We find considerable polarization between Democratic and Republican respondents’ evaluations of these two groups (the feeling thermometer scores run between 0 [very cold] and 100 [very warm]). Nearly all Republicans are clustered in the upper left: giving police high ratings and BLM low ratings. On the other hand, Democrats are dispersed throughout the space. Democrats have nearly identical mean ratings of the police (56.1) and BLM (55.8).

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The 2016 election is reminiscent of the 1968 election in the salience of law and order issues. Using feeling thermometer data from the 1968 American National Election Study, Bayesian multidimensional scaling finds a stark law and order divide running from Humphrey voters on the left to Wallace voters on the right, with Nixon voters in between:

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We see the same divide on a question specifically about how best to deal with the problems of rioting and urban unrest. The urban unrest question in the 1968 ANES asked respondents where they and the candidates stood on a seven-point scale ranging from “solve problems of poverty and unemployment” on the left to “use all available force” on the right. Here again, Wallace was able to pick up a substantial amount of voters most in favor of using force to deal with urban unrest.

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Ideological Perceptions of Pence and Kaine

Below we update an ongoing project that uses Bayesian Aldrich-McKelvey Scaling to estimate voters’ ideological perceptions of political figures on the 2016 stage. Because the 2014 Cooperative Congressional Election Study asked 50,000+ respondents to place national political figures (like President Obama) and state-level figures like their governor and senators on a liberal-conservative scale, we can use the Bayesian Aldrich-McKelvey scaling procedure to estimate their positions in a common ideological space. We can also estimate credible intervals (the Bayesian analogue of confidence intervals) that reflect uncertainty in the recovered scores.

The survey respondents seemed to do a good job of placing these figures on the liberal-conservative scale. Bernie Sanders is the furthest left, while Ted Cruz is the furthest right. Tim Kaine is the most centrist Democrat, while Chris Christie and Jeb Bush are the most centrist Republicans. Mike Pence has virtually the same score as Marco Rubio: to the right of moderate Republicans, but not as far to the right as Cruz and the Tea Party.

Also noteworthy is that the Supreme Court is nearly dead center in these scores (based on 2014 data). We wait to see if the Court will be placed further leftward by 2016 CCES respondents.

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Scaling Voters, Candidates, and Groups with Feeling Thermometers

Below we use Bakker and Poole’s Bayesian multidimensional scaling method to scale voters, candidates, and groups together using respondents’ feeling thermometer ratings. Specifically, the UGA module of the 2015 Cooperative Congressional Election Study asked 1,000 respondents to rate how warmly or coldly they felt about a series of candidates and groups (e.g., investment bankers, Muslims, Evangelical Christians, etc.).

Based on these thermometer ratings, we can jointly scale voters and these candidates/groups such that greater distances correspond to “colder” ratings and smaller distances correspond to “warmer” ratings. The main advantage of the Bakker-Poole method is that it avoids pushing candidates/groups too far to the edges of the space. That is, there are some voters to the left of Sanders and the right of Trump–as a general rule, candidates shouldn’t be the most extreme points in the space. As a technical matter, this is because Bakker-Poole MDS uses the log-normal distribution to model the thermometer ratings, which reflects the intuition that smaller distances should have smaller error variances.

The results are shown below. Because we are using a Bayesian approach, we can easily extract measures of uncertainty for the point locations (Jacoby and Armstrong have also developed a bootstrapping approach to estimate uncertainty intervals for MDS solutions). Accordingly, we also plot the 95% credible intervals for Donald Trump, Marco Rubio, Jeb Bush, Bernie Sanders, Hillary Clinton, and Pope Francis.

Several things stand out. First, there is a clear liberal-conservative division not only among candidates and partisans, but also social groups. There are two distinct clusters of Democratic and Republican candidates, voters, and groups.

That being said, there are also internal divisions within each of the party clusters. Both Clintons and President Obama are highest on the second dimension, while we find Sanders and several liberal groups lower on the second dimension. Socialists are placed the furthest left of all groups. On the Republican side, Trump and Jeb Bush anchor opposite ends of the second dimension. As we would expect, more Republicans have high second dimension scores (closer to Trump) than low second dimension scores (closer to Jeb Bush).

There is more uncertainty associated with the locations of the Republican candidates than with Hillary Clinton or Bernie Sanders. Hillary Clinton is also closer to the interior of the Democratic Party than Trump is to the interior of the Republican Party.

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