WA Senate - Murray +3 - Elway Research.

[Senator Incitatus]

If the Democratic Party loses this race, they might actually cease to exist within a decade.

[Senator Incitatus]

That is possible by blanket Primary Laws, do you think that there is a real chance Murray could lose to a GOPer like Tiffany Smiley. And do you actually think that the GOP Wave will be bigger than both 2010/2014 combined?

No, there isn't a realistic chance. If Murray does lose, forget 2010 or 1994. That would be a wave on par with 1894.

That's probably overstating things; 1894 was a crushing defeat that essentially reduced the Democrats to a regional status and gave Republicans seats they hadn't dreamed of winning in years. 1894 would be like Murray, Durbin, and Wyden all losing, maybe even Van Hollen or Schumer, reducing the Democrats to stable footing in just California and New England.

The truth is that there's a lot of ground between 1994 and 1894 because Republicans have been the minority party for nearly a century. They haven't had many solid-but-not-dominant majorities, which is what we're looking at.

[Senator Incitatus]

That is possible by blanket Primary Laws, do you think that there is a real chance Murray could lose to a GOPer like Tiffany Smiley. And do you actually think that the GOP Wave will be bigger than both 2010/2014 combined?

No, there isn't a realistic chance. If Murray does lose, forget 2010 or 1994. That would be a wave on par with 1894.

That's probably overstating things; 1894 was a crushing defeat that essentially reduced the Democrats to a regional status and gave Republicans seats they hadn't dreamed of winning in years. 1894 would be like Murray, Durbin, and Wyden all losing, maybe even Van Hollen or Schumer, reducing the Democrats to stable footing in just California and New England.

The truth is that there's a lot of ground between 1994 and 1894 because Republicans have been the minority party for nearly a century. They haven't had many solid-but-not-dominant majorities, which is what we're looking at.

I'd be curious to know what the House and Senate results would look like if the Democrats suffered 1894-scale losses, particularly the House.

It's very difficult to compare exactly because the Solid South skews results quite a bit. Republicans won literally every seat they could in 1894 save about ten. And you really don't get those kinds of landslides, particularly for Republicans, outside of presidential elections. It was a unique historical moment.

But, with that huge grain of salt, I'll crunch some numbers for what it's worth. Discounting the Populist result, Republicans got 56.1% of the two-party vote in 1894. That's R+12.2. There was one Trafalgar poll with a wider margin (R+14), but it's just one extreme outlier. I think there have been only two double-digit polls.

Using Cook PVI and the old map, that would project:

• A 318-117 Republican majority in the House. (With the new map, this might actually be larger; Democrats have created a lot of D+10 seats at the expense of some of their safer seats.) A quick glance at the charts shows that the Democrats would largely be confined to the city centers, not even their suburbs. Republicans would be winning seats throughout New England and moderate/minor cities like Indianapolis, Las Vegas, Buffalo, Providence, Camden.
• A 60-40 Republican majority in the Senate, after gaining every available seat except California, Hawaii, Vermont, and Maryland. This does not include the possibility of Joe Manchin and/or Angus King leaving the Democratic caucus.
• Likewise, Republicans would gain every Democratic governorship except California and Hawaii. However, Democrats would actually gain the governorships of Maryland and Massachusetts. By pure PVI, they'd also gain Vermont, but that seems extremely unlikely.

edit: Based on a faulty understanding of PVI; see below.

A landslide like this isn't outside the realm of historical imagination, but it's definitely outside my current imagination unless we get a whole string of R+10 generic ballot polls, maybe as the result of a real scandal rather than just the traditional scandal of competence we see when one of the sclerotic party machines enters power every four years or so.

And then we'd start to see a snowball effect within the Democratic Party as things collapse. After 1894, many people speculated that the Democratic Party was over, and it arguably was, at least as it had existed prior. There is a solid historical argument to be made that the Populists wore the Democratic label as a skin suit in the 1896 elections; the hard-line Bourbons were permanently dead. After an election like this, you might see the Democratic Party turned into an urban minority-rights advocacy group.

[Senator Incitatus]

R+12 would mean every district where Biden got less than 58% (of the two party vote)  in would flip.  Using the new maps and estimates based on what I think are likely for the unfinished maps, it would be something like a 273-162 Republican majority.  Not sure how you are getting 318-117.  A seat like VA-10 (Biden + 18) would be very close in this scenario but wouldn’t flip.

A couple things that could account for the discrepancy:

• Like I said, I'm using the old map here (for convenience); the 318 number is pre-adjustment. Maybe I'm completely off on the effect of the new maps, too. The general sense I've gotten is that they create more Likely D seats (which would still flip in this scenario) at the expense of Titanium Safe seats.
• I'm using Cook PVI, not just the Biden margin. It's more thorough, though I admit that straight-ticket voting is increasingly common so that using Biden margin isn't as ridiculous as using "Gore margin" would have been.
• I did the counting by hand, going down a list of seats by PVI. Could just have miscounted by ten or twenty.

[Senator Incitatus]

R+12 would mean every district where Biden got less than 58% (of the two party vote)  in would flip.  Using the new maps and estimates based on what I think are likely for the unfinished maps, it would be something like a 273-162 Republican majority.  Not sure how you are getting 318-117.  A seat like VA-10 (Biden + 18) would be very close in this scenario but wouldn’t flip.

A couple things that could account for the discrepancy:

• Like I said, I'm using the old map here (for convenience); the 318 number is pre-adjustment. Maybe I'm completely off on the effect of the new maps, too. The general sense I've gotten is that they create more Likely D seats (which would still flip in this scenario) at the expense of Titanium Safe seats.
• I'm using Cook PVI, not just the Biden margin. It's more thorough, though I admit that straight-ticket voting is increasingly common so that using Biden margin isn't as ridiculous as using "Gore margin" would have been.
• I did the counting by hand, going down a list of seats by PVI. Could just have miscounted by ten or twenty.

Cook PVI is not the margin of victory.  It’s the percentage point amount that a district leans to one party vs the national popular vote.  A district where Biden got 56% of the vote in 2020 is a D+5 district.  In an environment where Republicans won by 12 (say 55-43), a district Biden won 57%-41% (D+6) would be tied in a uniform swing situation.  

Thanks for clearing this up; I was going off a few pre-2020 that explicitly say the opposite, but I see they're contradicted directly by the Cook site. Did they previously base it on margin or something?

edit: I have been specifically using David Byler's characterization, which had been authoritatively cited on Wikipedia (I've since removed it): For example, if a Democratic presidential candidate won the popular vote nationally by five points, he or she might win a D+2 state (which leans two points toward Democrats) by seven points. And if a Republican won the popular vote by three points, he or she might win a D+2 state by one point.

Serves me right for trusting a journalist.