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How Representative of the U.S. Is the 2015 Senate?

Not very, but more so than it used to be. A story in three charts.
U.S. Capitol. (Photo: njene/Shutterstock)

U.S. Capitol. (Photo: njene/Shutterstock)

We have been collecting the demographics of senators since 1976, including detailed information about what church they attend, because race, ethnicity, gender, and religion are critical socializing forces that determine the way members of Congress behave. Our data on the incoming class of senators suggest that in some ways the U.S. Senate is becoming more representative of the U.S., but in many ways, the Senate remains a very unrepresentative body.

Historically, the U.S. Senate has been a white male institution, and despite recent gains among women and minorities, it remains dominated by a statistical minority (white males today make up about 1/3 of the U.S. population).


It probably will come as a surprise to no one that women are vastly underrepresented in the U.S. Senate. Despite the fact that women make up just over 50 percent of the United States population, a total of only 34 women have served in the Senate in all of U.S. history. This year there will be just 20 female senators. There were 20 women last year as well, and despite the defeat of Mary Landrieu (D-Louisiana) and Kay Hagan (D-North Carolina) to male candidates, two other women were elected in other states—Joni Ernst (R-Iowa) and Shelley Moore Capito (R-West Virginia).

Over the last 30 years, several demographic changes have occurred in the U.S. Although the percentage of the population that is African American has largely remained stagnant (in 1970, African Americans made up 11 percent of the population, today they make up 12.6 percent), a larger share of the United States is now Hispanic (4.4 percent in 1970, 16.3 percent in 2010) or Asian (0.8 percent in 1970, about five percent today). Still, only nine African Americans have ever been either elected or appointed to the Senate—two during Reconstruction, one in the 1960s/’70s and six since 1993—along with only eight Hispanic Americans and six Asian Americans.


The religious adherence of the U.S. population has also been changing. Over the last 30 years, there has been a drastic increase in the number of Americans who do not adhere to any religion. Today, about 16 percent of the United States’ inhabitants are unaffiliated with a specific religious tradition. At the same time, the number of mainline or evangelical Protestants (the two dominant Christian traditions) has decreased from over 60 percent of the country to fewer than 50 percent. But the incoming Senate is not reflective of the secularization of the U.S. Now we have just two senators who publically admit that they are not affiliated with a church—one less than the 113th Senate.


The U.S. Senate is designed to be unrepresentative. As long as women, racial minorities, and people adhering to different religious traditions (or no religion at all) do not congregate in specific states, the Senate is unlikely to be reflective of the U.S. population as a whole.

The consequences of this unrepresentative demographic profile are several. As many scholars have discovered, elected officials are guided by their personal backgrounds that go beyond strategic considerations. In other words, by knowing the political tendencies of a demographic group in the general population, we can often predict how that group’s representatives will perform when they hold office. When it comes to sex, men are more conservative than women. Similarly, whites are far more conservative than non-whites. A Senate that is overwhelmingly male and white, then, implies a more conservative legislative body than the population it represents.

The story is a little bit more complicated when it comes to religion. Mainline Protestants, Jews, and Mormons are over-represented in the Senate, but these groups tend to be moderate, liberal, and conservative, respectively, relative to the rest of the population. On the other hand, evangelical Protestants, members of historically black churches, and seculars are under-represented in the Senate, and these groups tend to be conservative, liberal, and liberal, respectively, compared to the rest of the population.

The extent to which the overall direction of public policy would change based on a Senate that is more reflective of the population’s religious characteristics is a mixed bag, and ultimately depends on whether one thinks it is desirable to replace mostly moderate mainline Protestants with more conservative evangelicals, more liberal black Protestants, and those who don’t attend church.

Regardless, given what we know about how different demographic groups behave and the make-up of the incoming Senate, we can expect it to be more conservative than the population.