1. Centrist moderate numbers are vastly overrated. See analysis from Geoffrey Skelly on 538 here. That same study links to another of his that points out how they mostly went to Trump last cycle and he only won by a few hundred thousand votes in a few select swing states that had very poor Dem turnout.
2. Per Rachel Bitecofer, a professor who specializes in electoral prediction models and largely nailed the mid-terms, they no longer decide elections.
3. Even allowing the moderate undecideds a seat at the table requires one to acknowledge who they are. 538 has another great study showing that they already have polarized views, they just don't associate strongly with a party despite sharing some non-trivial core ideology.
4. The entire Trump campaign that worked in 2016 was to make the race so distasteful as to keep most moderates from even showing up. Bannon has spoken about this at length so I won't give any of the conservative rags he did so the clicks for covering it. The entire strategy was to mobilize a largely untapped base of alt-right shitheads while making the "moderate" suburban white voters stay home because of how unpleasant politics had become. It worked very, very well.
The Democratic party won the mid-terms because they got moderate dems AND a larger segment of the base than in 2016 to show up.
All polling shows that moderate dems are, like they did in '18, going to show up specifically to vote against Trump, regardless of the Dem candidate. "Moderate" independents broke hard for Trump in '16 already. So either they caught a cup of reality since then or they're already lost regardless of the Dem candidate.
The only candidate with a meaningful X factor to turn out voters is Sanders. There is a massive wealth of <40 voters to be tapped into. If Sanders can do that, which all polling says he and only he can, that is a paradigm shift. He doesn't need to to massively move the needle either.
<30's turned out at about 50% in 2016, as compared to about 58% across the whole field. They'll account for an even larger share of the electorate in 2020. Clinton lost this group in two ways:
1. she got worse turnout than Obama did in both '08 and '12.
2. when <30's did turn out they were far more likely to vote 3rd party. Third party candidates combined for 3% of the vote in 2012. That was up to 8% in 2016. A lot of that went to Gary Johnson and Jill Stein. The former was the "conservative moderate" and libertarian alternative to Donald Trump. Sanders, the longest tenured anti-foreign engagement politician in the country, plays well to that audience even if they don't care for his healthcare policies. The Stein voters were a huge loss for Clinton and likely were a big part of deciding at least two or three swing states. Sanders would almost certainly bring most of them back in the fold.
Conventional political strategy at this point is a both-sides-ism. To believe it you need to believe that there is a vast ocean of moderate undecideds, when all assessments prove the opposite. That those moderates are willing to swing based on candidates and aren't going to instead vote on a single personal issue, like immigration, abortion rights/lack thereof, etc.. That even if some margin of them could be swung they're going to be swung by anything but the economy.
Its wishful, naive thinking. Unless the economy tanks before the election the Dem path to victory is running a candidate who energizes untapped left voters, which amounts to the youth and hispanic voters. Sanders leads both by a wide margin.
That candidate also needs to be unflappable and unwavering in the face of political criticism. The major news networks, CNN and MSNBC included, put far more time digging into Clinton's shit than Trump's shit in '16. That will happen again. They did this because for every "its over" story they had on Trump his support would bounce back within a week and it wouldn't matter. Telling the truth about Trump had less media draw than telling stories about Clinton.
Sanders is that guy too. No one in the Dem Primary has been able to make anything stick to him. Nothing from MSNBC or CNN either. How Fox News covers him is irrelevant because their viewership is already in lockstep with the Trump agenda.
Chuck Todd putting a conservative op-ed on a podium by calling Sanders supporters brownshirts shows the flaw at MSNBC. They went for the Nazi imagery over the actual part that had merit: To win now you need a higher floor of support than ever before as that makes you teflon from the disingenuous reporting we get from for profit media. Sanders is the only candidate on the left who has that.
His supporters are the polar opposite of Trump though. Trumpers are there for the pain and suffering he causes to others. Sanders supporters are there because of the pain and suffering they're experiencing right now in the broken system we have today.
I know multiple people have already quoted you and said how good this post is, but I think it deserves another commendation. Bravo!