Could your vote swing the Senate?

Hello, it’s Rose this week! I write for Datawrapper’s blog. Today’s Weekly Chart is half traditional election map, half whimsical what-if.

It’s less than a month until election day in the United States, and last weekend I finally made time to request an absentee ballot. As I navigated through a mess of city, state, and federal websites, all giving different instructions, it was impossible not to ask myself: Is this worth the trouble? How much does my vote matter?

Now obviously I believe in democracy. But as a lifelong resident of deep-blue Brooklyn districts, I’ve never actually gotten to cast a vote in a competitive general election. And while not everyone’s position is this extreme, in any democracy it’s just true that your own vote will basically never affect the balance of power.

Basically never. But not literally, technically, absolutely never. It’s not that unusual for the Senate to be held with a one-seat majority. And if you managed to cast the vote that decided that race — if your state was at a totally deadlocked 50-50 tie — then you’d end up an unlikely kingmaker for the entire country.

This won’t happen, but it could happen, and that alone is fun to imagine. To see how likely it is in each state, I took a look at FiveThirtyEight’s 2022 Senate model, which includes a “Voter Power Index” that measures the relative odds of exactly this scenario. In their model, there are three main factors that affect your ballot’s power:

1. How many other people vote in the same race

Everyone has a bigger role in choosing their mayor than in choosing their senator. The more votes are cast in a race, the less any single one of them matters. That means states with small populations (like Vermont) and low projected turnout (like Louisiana) both give a boost to the influence of voters who actually show up.

2. How close the race is

It doesn’t matter how small the electorate is if there’s no disagreement within it. When your state has a strong and consistent partisan lean, the race won’t be won by a margin of just one vote — it might not even be as close as a million votes. So although very few people are eligible to vote in North Dakota, its strong Republican tilt means the power of their ballots is still quite low.

3. How closely your state reflects the national mood

Although different names are on the ballot, Senate elections aren’t independent events. Competitive races tend to fall to one party or the other in a somewhat predictable order. It’s pretty likely that the Senate as a whole will be controlled by whichever party Georgia voters choose; Idaho could probably only be won by a Democrat in a year with a total nationwide meltdown of the Republican party. So even if you manage to cast your senator’s winning vote, they’re only likely to be the chamber’s decisive vote in a few swingy states.

If you’re registered in Nevada (a seat that’s very likely to determine control of the Senate) or New Hampshire (a tiny state without a strong partisan lean), there’s a not-incalculably-tiny chance that you could end up in a decisive role. As for me, I could safely leave it to my fellow New Yorkers to reelect Chuck Schumer without help this year. I’ll probably fill out the ballot anyway — and be a bit grateful that it doesn’t all come down to me.

That's all from me for today! Come back next Thursday for the very first Weekly Chart by our new writer Veronika!