Small states' outsized political power (Part II-A: Measuring the effects in the Senate)

The first post in this series summarized the history of small states' outsized political power. The Constitution embodies a number of compromises reflecting the concerns of the era. The Senate, which affords all states exactly two votes, reflects the Framers' concerns that populous states would overwhelm small ones. The House of Representatives was meant to expand over time, but its growth did not keep pace with the population, and its size plateaued a century ago. The Electoral College allocates president-choosing authority by amalgamating these two systems.

The second part of the series shifts the focus from history and design to present-reality and outcomes. (The third part will explore the implications of proposed reforms.) The analysis proceeds in the same format: Senate, House, and Electoral College.

Before diving in, some caveats. First, the analysis that follows relies heavily on Census data from the July 2016 survey. Not all people are voters, for diverse reasons having to do with age, former incarceration, immigration status, barriers to voter registration, and even apathy or intentional disengagement. Second, this evaluation risks conflating "rural" with both "small-state" and "Republican." This impulse is unpacked elsewhere in this blog, and this analysis is one among various that convincingly show a pro-Republican rural shift, at least in presidential politics. Additionally, the "rural" and "small-state" labels do overlap meaningfully, albeit imperfectly. (For more discussion of this, see here.)

The Senate

Viewed from any of several angles, small states enjoy outsized power in the Senate. The most obvious of these is mathematical: each state elects two senators, irrespective of its population. California, the nation's most populous state, had an estimated 2016 population of 39.3 million. The least populous state, Wyoming, comprised 585,000 people according to the same sample. Thus, the Senate-clout of the average Wyomingite was roughly 67 times that of the average Californian. If the U.S. population were spread equally across the 50 states, each senator would represent 3.2 million people, which is roughly what prevails in Indiana.

Although they may be in rapid decay, the Senate has historically adhered to strong internal norms, and seniority has been especially important. Thus, the longevity of senators is a crude metric by which we might measure states' power relative to one another. The two tables that follow perform just such a crude analysis:

Current U.S. Senators - Tenure of Office to 2016

Rank	State	Senator A Since	Years	Senator B Since	Years
1	CA	1992	24	2016	0
2	TX	2012	4	2002	14
3	FL	2000	16	2010	6
4	NY	2008	8	1998	18
5	PA	2006	10	2010	6
6	IL	1996	20	2016	0
7	OH	2006	10	2010	6
8	GA	2014	2	2004	12
9	NC	2014	2	2004	12
10	MI	2000	16	2014	2
11	NJ	2006	10	2013	3
12	VA	2012	4	2008	8
13	WA	2000	16	1992	24
14	AZ	2012	4	1986	30
15	MA	2012	4	2013	3
36	NM	2012	4	2008	8
37	NE	2012	4	2014	2
38	WV	2010	6	2014	2
39	ID	2008	8	1998	18
40	HI	2012	4	2012	4
41	NH	2008	8	2016	0
42	ME	2012	4	1996	20
43	RI	2006	10	1996	20
44	MT	2006	10	2014	2
45	DE	2000	16	2010	6
46	SD	2014	2	2004	12
47	ND	2012	4	2010	6
48	AK	2014	2	2002	14
49	VT	2006	10	1974	42
50	WY	2007	9	1997	19

The two halves of this chart indicate the fifteen most- and least-populous states. On a per-senator basis, the large states actually have a longer average tenure (9.8 years) than the small states (9.2 years). Seniority, described above as a key feature of Senate life, attaches to an individual senator, not his or her seat. It is beyond the scope of this series to analyze how much seniority figures into voters' choices and how the data above may have been affected by unique conditions in one or another election. 

In any case, the data are strikingly different when partisan alignment of these seats is tracked over time:

U.S. Senate Seats by Party-Control Lineage

Rank	State	Senator A Party	Same Since	Years	Senator B Party	Same Since	Years
1	CA	Democrat	1992	24	Democrat	1968	48
2	TX	Republican	1992	24	Republican	1968	48
3	FL	Democrat	2000	16	Republican	2004	12
4	NY	Democrat	1976	40	Democrat	1998	18
5	PA	Democrat	2006	10	Republican	2010	6
6	IL	Democrat	1996	20	Democrat	2016	0
7	OH	Democrat	2006	10	Republican	1998	18
8	GA	Republican	2002	14	Republican	2004	12
9	NC	Republican	2014	2	Republican	2004	12
10	MI	Democrat	2000	16	Democrat	1978	38
11	NJ	Democrat	1982	34	Democrat	2012	4
12	VA	Democrat	2006	10	Democrat	2008	8
13	WA	Democrat	2000	16	Democrat	1992	24
14	AZ	Republican	1994	22	Republican	1986	30
15	MA	Democrat	2012	4	Democrat	1978	38
36	NM	Democrat	1982	34	Democrat	2008	8
37	NE	Republican	2012	4	Republican	1996	20
38	WV	Democrat	1968	48	Republican	2014	2
39	ID	Republican	1968	48	Republican	1980	36
40	HI	Democrat	1976	40	Democrat	1968	48
41	NH	Democrat	2008	8	Democrat	2016	0
42	ME	Independent	2012	4	Republican	1978	38
43	RI	Democrat	2006	10	Democrat	1968	48
44	MT	Democrat	2006	10	Republican	2014	2
45	DE	Democrat	2000	16	Democrat	1972	44
46	SD	Republican	2014	2	Republican	2004	12
47	ND	Democrat	1968	48	Republican	2010	6
48	AK	Republican	2014	2	Republican	1980	36
49	VT	Independent	2000	16	Democrat	1974	42
50	WY	Republican	1976	40	Republican	1968	48

Viewed through a partisan lens, small-states' Senate tenure is significantly longer than that of large states. (Note that no "same since" date precedes 1968. Treating the 1968 election as a realigning one, I truncated party control to this year as a clumsy way of controlling for the shifting "meaning" of Democrat/Republican.) Single-party control of a Senate seat averaged 19.3 years for the fifteen largest states but 24 years for the smallest ones. Also, while Democrats currently control 19 of the 30 Senate seats in large states, in small states there is a 14-14 tie between the two major parties. (Maine and Vermont each have an independent senator who caucuses with the Democrats.)

Again, this is crude arithmetic which may or may not tell a meaningful story about political power. But one reading of these data is that small-state Senate contests allow Republicans as a whole to over-perform relative to large-state contests and then hold those seats for multiple terms.

A third way to examine this issue is to index Senate performance to presidential election results. This analysis argues that, while Senate Democrats out-performed expectations in the 2008, 2010, and 2012 elections, those were exceptions that proved the rule. "Republicans...start with a leg up in the Senate, because Democratic voters are concentrated in fewer states." This more-states-with-fewer-votes phenomenon was illustrated powerfully in the 2016 election, where Hillary Clinton earned nearly 3M (2.1 percent) more votes than Donald Trump, yet he carried 30 states to her 20.

A final view (though not the only one remaining) is this: it is possible for just 17 percent of the U.S. population to elect a majority of the U.S. Senate. It's the lowest such threshold in our nation's history, due to the continued growth of the population while the number of states (and therefore, senators) has remained fixed since 1959.

We should not forget that the Senate bestows this power on small states by design. However, as the country's population has increased by a factor of more than 80 and the number of states has nearly quadrupled since the Founding, what was once seen as a vital protection against inter-state caprice may now be a source of veto power in a constitutional system already rife with veto points.

Part II has been broken into two parts. The next section addresses effects of small states' power in the House and Electoral College.

Next Time: Part II-B, the House of Representatives and the Electoral College