November's presidential election marked yet another occasion when the winner, President Donald Trump, secured the office by a narrow majority.
This has become an increasingly common way to win for both parties. Politicians love to use the phrase "landslide victory," but it is a concept of the past. Since 1972, there have been only two elections—Nixon’s 1972 re-election and Reagan’s 1984 re-election—that were decided by a spread of over ten points.
Five of the fourteen elections since 1972 were won by five to ten points, four by a margin of zero to five points, and two where the victor lost the popular vote. The last time the point spread exceeded five was during Barack Obama's 2008 election.
A main reason elections are getting tighter is that more Americans are identifying with one of the two main political ideologies.
In 1992, the largest block of Americans referred to themselves as political moderates, at 43%. Conservatives made up 36%, and liberals accounted for 17%. Fast forward two decades, and the share of moderates has dropped nine points while the gap between conservatives and liberals has narrowed.
Within America’s two major parties, the decline of moderates is even more pronounced. Twenty years ago, 58% of Republicans identified as conservative, while 33% considered themselves moderates. In Gallup’s most recent survey, the share of conservatives in the Republican Party has swelled to 77%, while the share of moderates declined to 18%.
The trends are even more significant in the Democratic Party. In 1994, 48% of Democrats identified as moderates, while the other half of the party was evenly split between conservatives and liberals. Today, the dominant ideology in the Democratic Party is liberalism at 55%. About a third identify as moderates, and the share of conservatives has fallen to single digits.
Consistent numbers are not available for Arizona, but this phenomenon is evident in election results.
This past November, there were only one in five precincts where a gap of zero to ten points existed between Trump and Kamala Harris. Another one in five precincts had a gap of ten to twenty points—hardly a close result for either candidate.
Over half of all voting precincts in the state were either very Republican or very Democratic, with candidates supporting their respective parties by over twenty points.
