For a column I wrote back during the 2016 presidential primaries, I interviewed a few folks who belonged to a very tiny minority: Seattle residents who donated money to Donald Trump.

One of them was a fellow who, surprisingly, described himself as a progressive (he also contributed to Democratic candidate Bernie Sanders). Naturally, I asked him why he supported Trump.

“I like Trump because he’s gonna [expletive] destroy the Republican Party,” he told me.

He may have been right.

There’s no need for me to recount all the political craziness that’s happened since the November elections. Suffice it to say that for the first time in a decade, Democrats now have the presidency and control of both the House and Senate, while Republican leadership is sharply divided over the party’s future, and Trump’s role in it.

Seattle, of course, has long been a Democratic stronghold. So you might have thought that even four years of Donald Trump couldn’t make this area any bluer than it already was.

You’d be wrong.

New survey data on political-party affiliation shows that the number of self-identified Democrats in King and Snohomish counties increased by 31% from 2016 to 2020 — that’s more than three times faster than the overall population growth (9%).


The data, which comes from market-research giant Nielsen, shows that in 2020, about 913,000 adults in our area identify as Democrats, up from 699,000 in 2016.

Where did they all come from?

The market-research data doesn’t tell us. But there is other data that shows how politics plays a role when people decide where to move. A recent study of county-to-county migration patterns reveals that people tend to relocate to places where they feel more politically at home. It also showed that, in particular, counties that are already extremely partisan — King County, for example — become magnets for such movers.

The Seattle area, of course, had a tremendous period of growth throughout the 2010s. It’s likely that a disproportionately high percentage of the new arrivals are politically liberal.

And as this area has become increasingly Democratic, it’s also possible that a higher percentage of conservatives have moved elsewhere. The market-research data shows that the median age for Seattle-area Republicans is significantly higher than for Democrats or independents. Since retirement is one of the major life changes that prompts a big move, it’s possible that a lot of conservative retirees are leaving this area.

Could the numbers also reflect that some local Republicans are switching parties? It’s certainly possible, as we’ve seen a growing number of high-profile defections — the so-called “Never Trumpers.”

In addition to the more than 900,000 Democrats in our area, there are 459,000 adults who consider themselves independent but who lean toward the Democrats. That’s a total of nearly 1.4 million who are either Democrats or lean Democratic, and it represents the solid majority (56%) of the total adult population in King and Snohomish counties.


And that’s more than double the Republican population.

About 306,000 adults in the two counties identify as Republican. Add to that an additional 235,000 independents who lean Republican, and the sum is 540,000 adults who are either Republican or lean Republican — just 22% of the total adult population here. (Pre-Trump, they made up a slightly higher percentage, at 24%.)

True independents — those who lean neither left nor right — number about 211,000, or 9% of the adult population in King and Snohomish. There are also roughly 339,000 folks who have another political-party affiliation, or who have none. Many of these are likely noncitizens who are ineligible to vote in the U.S.

The data comes from surveys conducted from February to August in 2016 and 2020. The more recent data set, of course, captures the early days of the COVID-19 crisis. The low number of Republicans could reflect a response to the Trump administration’s response to the pandemic.

Demographic profiles show that in addition to being younger than Republicans, Democrats in our area have a lower median net worth (suggesting a lower level of homeownership), even though the median household income is almost identical. The median represents the midway point, meaning half are above and half are below. (Note: This data includes those who lean Democratic or Republican.)

Seattle-area Democrats are more likely to be single and also have a higher level of educational attainment than Republicans, on average. Both groups are a little less diverse than the total adult population here. Independents (among those who don’t lean left or right) are more diverse, with 37% being people of color.

Nielsen surveyed roughly 1,100 adults age 18 and older in King and Snohomish counties for both the 2016 and 2020 releases.

Nielsen also surveyed in Pierce County, which tends to be somewhat more conservative than King and Snohomish (though still a blue county in recent presidential elections). But in Pierce, too, the data shows that the number of self-identified Democrats surged by more than 30% from 2016 to 2020.

Thirty-one states, plus the District of Columbia, ask citizens to declare their political-party affiliation when they register to vote. Washington is among the 19 that do not, so there is no public-records data on party affiliation here.