Taking that attitude you're showing you're not here in good faith.

If you want good faith arguments perhaps don't start with condescending comments about "kindergarten" level civics and have enough charity to at least start from the premise that it might actually be you who's wrong rather than just assuming that any argument you don't agree with must be the result of your interlocutor being kindergarten level dumb.

You construct a twisted, narrow interpretation so that you can walk out on it and say look at this very narrow interpretation, explain this narrow interpretation.

Followed by...

Do they lose? Do they win?

Broad and wide-ranging narrative ... anyone?

And then you go on to tell a story about what each president 'would have done' which, I presume you must have gained from direct personal conversations with them, unless... Oh, you're not just believing things they tell the newspapers... You sweet summer child...

what would happen if they won consistently and overwhelmingly? They'd move left. They could do left things, without losing the next election. This is pretty simple.

It might seem simple to you. But it contains two hidden premises and two logical flaws.

The first hidden premise is that they actually want to move left (and so would take an opportunity to do so). You've not yet made a case that they do. A scattering of slightly-left-of-neocon policies is not very convincing.

The second premise is that each event is a response to the last and not to any of the hundred other factors in American politics at the time. Again, just showing one thing followed another does not prove it was caused by it.

The first logical flaw is that you've still not provided a mechanism by which successive democratic campaign teams know somehow why they lost, that it was their slightly leftist policies and not, again one of the other hundred factors in politics at the time.

The second logical flaw is that you've still not explained why democrats need an actual election to find out that lots of leftists will vote for them. Why can't they just poll, like everyone else does? They presumably rely on polls to tell them what policies these non-voters want, so why do they need an actual election victory to learn that in four year's time these people will likely vote for them. Why can't they just ask? That's the normal way all other political strategies are worked out - focus groups, polls, town meetings... You're singling out willingness to vote as a fact about potential voters which is somehow inaccessible to the democrat strategists without the proof of an actual election win, but assuming other facts, like the policies they'd like, can be ascertained. Why?