In posts from recent weeks, I wrote about how the Senate underrepresents citizens from populous states and minorities. However, the Senate has also consistently underrepresented Democratic voters for the past 30 years. Over the past three decades, the Senate has favored the Republican Party. Since 1980, there have been 17 sessions of Congress. Democrats have held the majority in the Senate 9 out of 17 sessions, or 52.9% of the time. However, the population represented by Democratic Senators has been greater than the population represented by the Republicans 15 out of 17 sessions, or 88.2% of the time. Democrats have been underrepresented in the Senate by between 5 – 18.5% every year since 1980. If the Senate were apportioned based on population, Democrats would have held the majority in many more sessions of Congress, which has a multitude of policy implications in areas including environmental regulation, health care, and assistance for the poor. Below are several figures that depict this state of affairs.
The above figure shows the percentage of the Senate that is controlled by each party. The dashed lines show the percentage of the population that each party represents. For instance, each Senator from California represents approximately 18.5 million people, while each Senator from Wyoming represents 270,000 people. The figure shows that the Republican Party is consistently overrepresented in the Senate, while the Democratic Party is underrepresented.
This figure shows the Senators that each state has elected since 1980. Blue areas represent Democrats and Independents, and red areas represent Republicans. The data for this plot came from this website.
The above figure shows the percentage increase or decrease in representation relative to population that each party receives because each state gets an equal number of Senators. These lines were created by subtracting the dashed lines from the solid lines in the first figure. In 1994, there were an unusually high number of Democratic Senators in populous states.
This figure shows the total misrepresentation in the Senate, which is the sum of the differences in population and senate representation for both major parties. For example, in 2002, the Democrats only held the Senate Majority with one Senator, giving them a 1% advantage in the Senate. However, Democratic Senators represented 15.8% more of the population than Republican Senators, which means that in 2002, the Senate misrepresented the population by -14.8%.
The last two figures show the advantage in seats and in population that each party had in the Senate for each session since 1980. Although the Senate majority has been held in almost equal amounts of time by both parties in the past 30 years, the population voting for Democratic Senators has outnumbered the population which voted for Republican Senators in all but two sessions of Congress.
The figures presented in this post show yet another glaring flaw in the Senate, and consequently, in our entire political system. The Senate is forming a barrier to social progress by underrepresenting voters in our most populous states, which are often the most diverse, cosmopolitan, technically advanced and socially sophisticated in the country. California has a population of more than 37 million people, which is greater than the population of the 21 least populous states of 35 million. The top five most populous states are California, Texas, New York, Florida, and Illinois, which collectively have a population that is larger than the 36 least populous states, 113 million vs. 111 million, respectively. Over the past 30 years, California has voted for Democratic Senators 80% of the time, and the top 5 most populous states have voted for Democratic Senators 63% of the time. This Senate is clearly not representing the population well and should be reworked.