The column was titled, “The Varied — and Global — Threats Confronting Democracy,” and the unbalanced representation presented by Birdsell’s data was meant to reinforce the point. “Demographic trends also are straining the American model,” Seib wrote by way of introducing the 70-30 figure.
Population projections from the University of Virginia’s Weldon Cooper Center for Public Service offer a slightly lower distribution: By 2040, the 15 most populous states will be home to 67 percent of the U.S. population and represented by 30 percent of the Senate. But, then, that’s already about the distribution — and it has been for a long time.
Let’s consider half of the population to start. In 2040, nine states will be home to half of the country’s population, according to the Weldon Cooper Center: California, Florida, Georgia, Illinois, New York, North Carolina, Ohio Pennsylvania and Texas. Between them, they will be represented by less than a quarter of the Senate.
Census data stretching back to 1790, though, shows that the most-populous states making up half of the country’s population have always been represented by only about a fifth of the available Senate seats. That includes 2016.
Flip the metric: The 25 most-populous states in 2040, holding half of the seats in the Senate (assuming no new additions to the union), will be home to 84.2 percent of the population.
In 2016, the 25 most-populous states were home to 83.6 percent of the country. In 1790, the most populous half of states were home to 82.2 percent of the population.
We can keep shrinking the number of states we’re looking at and the same consistency emerges. The most populous third of states has consistently been home to about 70 percent of the population.
The most populous quarter of states — represented by a quarter of the Senate — has consistently been home to around 60 percent of the population.
The most-populous tenth of states has consistently been home to at least a third of the population.
As the segment of states we’re looking at has gotten smaller, you’ll notice that the percentage of the population that lives in those states has increased more rapidly in the Cooper Center’s projections. In 2016, the five largest states are home to 37.2 percent of the population; by 2040, those five most populous states will be home to 39.6 percent of the population. That means that an additional 2.4 percent of Americans will be crammed into the constituency of the same 10 Senate seats, but that’s only slightly more than in 1870, when 38.5 percent of the country lived in the five most populous states.
Which is to say that Senate representation in 2040 is projected to be more lopsided than it is now — but skewed toward the biggest states and not by much overall.
We can visualize this as a curve.
In 2016, a quarter of Senate seats represent 59.5 percent of the population. That same quarter will represent 60.3 percent of the population in 24 years. The difference is real, but subtle.
That list of the largest states outlined above reveals one reason that the Senate tends to work anyway: Senators from Texas and senators from New York don’t tend to vote the same way, nor do senators from the small states of Vermont and Wyoming.
Last April, we noted that the Senate was increasingly casting votes in which senators representing a minority of the population were defeating senators representing most of America. Whether that trend continues is one thing. What’s important to note is that, since the earliest days of the United States, it could have.