If (some) American voters cannot or will not grasp these facts, they themselves--and not Harris and her team--have failed their country.

Most voters do not agree with that framing. They don't believe that Donald Trump is so beyond the pale that he cannot be considered a legitimate choice for President. The number of people who either intend to vote for Trump or who are Harris voters that aren't "double haters" is more than a majority.

Which makes it very possible for Harris and her team to also fail their country. The voters have made it pretty clear that the most important issue to them is the economy. More than saving democracy. They care about the economy.

Democrats can lament that fact. They can call the voters stupid or ill-informed or "failing their country." But they cannot change that fact during a three month campaign. You can change their perceptions of the candidates, you can inform them of new things about the candidates, you can argue over whose policies are better, etc. But you can't change who the voters are in the space of a few short months.

Which means that Harris and her team need to get voters to believe that she will be a good steward on economic issues. And it is very hard to do that if the voters believe they don't know what she would actually do on the economy. "Not be Donald Trump" is certainly something, but it doesn't provide much guidance for what a Harris Administration would look like on economic issues.

Which is why Harris' campaign choices matter. Voters know, intuitively, that the economic priorities of (say) a President Bernie Sanders would be different than those of a Tammy Baldwin or a Cory Booker - they're different people, they have different issues that they care about. And voters want to know where Harris' priorities lie - why she wants to be President, rather than why just why she wants to beat Donald Trump. There are some valid reasons perhaps not to give them want they want, but Democrats will pay a political cost for not doing it.