voting in the 2020 primary

After the 2016 election, I firmly decided that I am not a Democrat any more. I'm pondering still voting in the Minnesota state primary, though.  The rules for our primary are slightly weird.  To get a ballot, I have to sign this statement:

"I am in general agreement with the principles of the party for whose candidate I intend to vote, and I understand that my choice of a party's ballot will be public information."
- https://www.revisor.mn.gov/rules/8215.0300/

That's not quite the same thing as swearing fealty to the Democratic party, so I think I may go vote tomorrow in the primary. My other party is Green, to whom I have checked the box on my state income tax form to send them a few bucks.  I think I've done that every year since 2016.  But that statement I'd sign is still true.  I am in general agreement with the Democrat platform.  It's a few key specifics where I differ, and where I'm convinced they need to change in order to win future elections.

The 2020 election is shaping up to become a repeat of 2016, with the anointed establishment Democrat coming to a decidedly anti-establishment electorate. How many times/years do I have to keep telling people that politics is no longer a left-vs-right landscape?  It's a critique of status quo policies that have left the broad majority of U.S. citizens feeling left behind, both economically and politically.

Don't believe me?  Then why is the largest voting bloc in the USA filled with the unimpressed?  In particular, look at the findings in these sections of that article.  Each time, ask yourself which Democrat would actually appeal to these people and get them to the voting booth?

• "Net Support of Policy, Rich Voters and Poor Nonvoters"
• "Net Support of Policy, Registered vs. Not Registered"
• "Differences in Ideology Between Voters and Nonvoters"
• "Median Income at Different Levels of Political Participation"

If Democrats don't bring a populist candidate to this election, then I predict another 4 years of Trump.  I would accept either Sanders or Warren in this populist category.  They arrive at similar populist policies by different routes (Sanders by empathy, Warren by evaluation).  I warned about the possibility of a Trump victory last time for this same reason, but nobody listened.