With the recent turnover in the U.S. Senate to a Republican majority, I was reminded that just over a year ago, the (then) Democratic majority of the U.S. Senate lowered the vote required to pass a motion for cloture (i.e., an action that cuts off a filibuster). Previously, it took 60 votes to make this happen; the recent action made a simple majority vote sufficient (except in certain cases, Supreme Court nominees, for example, which retain the 60-vote requirement).
In the spirit of "chickens coming home to roost", this got me to thinking: what is the smallest number of people that could elect enough Senators to "stop the government" by blocking a cloture motion; that is, how few voters could enable a minority of Senators to continue to filibuster and prevent the Senate from acting.
Turns out, it's tiny: just barely over one percent (~1.1%) of the U.S. population can elect enough Senators to do this. Here's the math:
- The U.S. population is approximately 314 million.
- Each state, of course, elects two Senators, so 25.5 states are enough to prevent a majority vote in the Senate and, thereby, block a cloture motion (i.e., both Senators from 25 states, and one from another). This number is chosen to avoid the situation where the Vice-President could cast the deciding vote in the event of a tie.
- The smallest 26 states in the U.S. have an aggregate population of about 59 million people — for purposes of this purely theoretical analysis, I'll call these the "Blocking States".
- I assume about half of the population is of voting age, so roughly 29.5 million people in the Blocking States could register to vote if they wanted to.
- On average, about half of eligible voters actually register to vote, so just about 14.7 million people can actually vote in the Blocking States.
- Usual voter turnout in the U.S. is abysmal, often as low as 25% – 30% of registered voters — so, I conservatively assume that 50% of registered voters, or 7.3 million actually vote.
- Because most elections in the U.S. have more than two candidates, the winning percentage vote is frequently around 45% of votes cast — so, I conservatively assume that the winning candidate receives 50% of all votes cast, or ~3.5 million votes.
What this means is that as few as ~3.5 million people (barely over one percent, or ~1.1%) can elect enough U.S. Senators to block a cloture vote, sustain a filibuster and prevent the government from acting.
These numbers are for a "mere" majority cloture vote. For the remaining cloture votes that require the (old) 60% vote, the number is an even smaller ~2.4 million voters (or less than one percent, a mere ~0.7%)