In looking at data from the American National Election Studies from 1952 to 2016, I wanted to get a better sense of how these trends--the perceived rise of independents, as well as the potential rise or decline of partisanship and party loyalty--has been recorded in presidential election years.
To garner a sense of the various electorates in presidential years, I first looked at the party identification, specifically including the "strength" of partisanship factor that is in the ANES data for the various years. For example, "strong" partisans (both Republicans and Democrats) could be compared to "weak/not very strong" partisan identifiers in both parties, while independents could be divided into "leaners" to one party over the other compared to "pure" independents.
For example, in 2016's presidential election, the break-down of the electorate showed that strong partisans (either Democratic or Republican in allegiance) was a combined 43 percent of the electorate; add "not very strong" partisans to their strong adherents and well over over two-thirds of the electorate (68 percent) identified with one of the two major parties.
But in taking into account the remaining 32 percent of the electorate who identified as "independent," only 9 percent said that they were "pure" independents (didn't lean to either party), and they split their vote in a fascinating divide among the two major parties' presidential candidates and third party candidates.
|2016 Presidential Vote Choice by Party Self-Identification
This trend has been noticeable over the past few presidential elections, but I wanted to go back (as far as ANES data would allow) to see what trends, if any, were in the past sixty years.
First, the trends of party self-identification, based on strength of party affiliation, for Democrats, Republicans, and those "pure" independents:
|American National Election Surveys (1952-2016): Democratic Self-Identification by Strength
|Gallup Poll U.S. Party Identifications (Republican, Independent, and Democrat), Yearly Averages, 1988-2015
With their levels of partisan "loyalty" (voting for their leaning party's presidential candidate), partisan independents need to be differentiated from the "pure" independents.
But was 2016 an exception to the rule when it comes to party loyalty among partisans and independents? The following graph presents a "spaghetti" display of tracking the presidential vote choice for the different categories of party self-identification and strength since 1952:
|American National Election Surveys (1952-2016): Partisan Self-Identification (by Strength) and Presidential Vote Choice
The darker the shading, the more partisan in terms of self-identification. In reviewing the trends, there appears to be two distinct "periods" of partisan loyalty when it comes to casting ballots for one's presidential candidate among partisan identifiers. First, the graph broken out to show from 1952 to 1988:
In taking the two periods and looking at the "loyalty" averages for each group of partisans:
Strong Republicans have shown the greatest consistency in their party loyalty, average 95 percent of the time voting for their party's presidential candidate since 1952, while it was only after 1992 that strong Democrats showed their party loyalty at 96 percent from the previous period of 87 percent.
Another interesting phenomenon also appears to mark the two periods differently: before 1992, weak and independent-leaning Democrats were well below their Republican partisan brethren, but after 1992, weak and independent-leaning Democrats increased their partisan loyalty to comparable to Republicans, who slipped in their partisan loyalty. But make no doubt: three-quarters to 80 percent of 'partisan' identifiers (excluding strong partisans) are loyal to their party's presidential candidates.
In other words, party "defections" from voting for the party's presidential candidates have been declining since the "moderate" era of the 1950s, especially among Democratic identifiers:
|American National Election Surveys (1952-2016): Democratic Self-Identification by Strength and Defections to Republican Presidential Candidates
But since 1992, with two notably "smaller defection spikes" for both Republicans (in 1996) and Democrats (in 2000), less than 2 out of 10 partisan self-identifiers have broken with their party loyalty and voted for the opposition presidential candidate.
In other words: with only one out of ten presidential voters as the "pure" independents so many have been calling for, partisan tribalism and loyalty is the norm for voting behavior, and we shouldn't be surprised it influences other aspects of our political environment.