I have anecdotally heard from some Republicans in Washington that they do not bother to vote, especially in non-presidential election years, as they feel that a Democrat will win the election anyway.

This is visible in county-level voting rates. The counties east of the Cascade mountains tend to be more conservative than the counties west of the Cascades, or areas surrounding metros like Spokane, and they also tend to have lower voter participation rates.

https://www.washingtonpost.com/business/2018/10/15/where-peo...

[Citation needed]

From what I see WA had a turnout of 75% compared to USA's 66%.

https://docs.google.com/spreadsheets/d/1h_2pR1pq8s_I5buZ5agX...

You're cherry-picking the most interesting election of the last five years. The recent primary was ~38% turnout.

https://www.seattletimes.com/seattle-news/politics/which-wa-...

Ok, so WA had 38% turnout for a primary so what? The whole point is that you need to compare it to other states to make any sense of the data.

Arkansas had <26% (457,856 votes / 1,762,024 registered voters) [1].

38% is looking pretty good.

[1]: https://results.enr.clarityelections.com/AR/112731/web.28556...

> The whole point is that you need to compare it to other states to make any sense of the data

I disagree with your assertion. Even so, alistairSH's conclusion: "We'd do well as a country to allow nationwide mail-in voting." like it was solution to solving lack of voting from renters, when cherry-picking data gets us 12 points at best. It might be part of a solution, but it's demonstrably not a majority difference.

All this presumes every possible vote is equally valid.