I have to remark on Blunt's unpopularity, given that it was the original topic of this thread.
Although I think Blunt would be favored in a Biden midterm, with numbers like this it wouldn't surprise me if he decided to retire rather than run for reelection. Blunt's approvals are no better than they were in 2016, when he almost lost to Jason Kander-and was rescued from defeat by Trump. Why exactly has Blunt always been so unpopular?
For the same reasons Mitch McConnell, of neighbouring KY, is: he's an aloof 'insider' who doesn't especially appeal to rural voters (or at least not nearly as much as Trump does), and who's not too good at campaiger (I'd say McConnell's better at it). Pollster describes Blunt's situation best:
Classic Washington insider in a state that despises insider politics in both parties, has a literal family of lobbyists, neither visible in the state (lives in DC and only owns a small condo in Springfield) nor a high-profile frequenter of national media, lackadaisical campaigner who is awkward in person, has a tendency to be very quick to campaign negatively in an off-putting way, uniquely poor rural outreach in a state where statewide candidates need it to be superb.
But there's a problem nonetheless for Missouri Democrats who think they can do the converse of what happened in 2018 (when a long-term
Democratic senator lost reelection in a
Republican midterm).
I don't think Kander running or not running (or even Nixon running or not running) while impact the outcome. MO's only become more polarized since 2016 (though Blunt did get a boost because Trump carried the state resoundingly that same day) and 2022 will be a Democratic midterm, which doesn't help Missouri Democrats. I agree with these quotes:
If even Claire McCaskill couldn't win re-election in 2018, there's no way any Democrat beats Roy Blunt in 2022, especially if Biden is President. Sorry, this one won't be too interesting.
Returning to the McConnell example - he's unpopular, but he's unpopular the same way Trump's unpopular with some suburban/religious voters (the word 'some' being key): they don't like him much as a person, and would prefer someone else, but they'll hold their nose and vote for him since he represents their interests (or at least more than his opponent does) and/or is better than a Democrat. There was noise that McGrath could beat McConnell, but funding doesn't cut it. McConnell's one of the most unpopular senators in the country, but KY's too red and too polarized to vote blue in a general election (gubernatorial elections are very different froms senatorial elections, especially in KY), and McConnell's too powerful to lose a primary. (Not that it matters - I think this term's going to be his last; he's in his seventh term.) Similarly, Kander and Nixon will also lose to Blunt. And a primary challenge, though it may gain a little traction, will fall flat at the end of the day.
Honestly, what'd be most interesting is what's about to happen - an open primary contest to determine Blunt's (Republican, doubtless) successor, since Blunt would win in both a primary and general, with his experience and establishment-ness being both a strength and weakness.