They've studied this. And the cause is is the following. Yes you get your base to turn out more. But extremism motivates their base even more than your own, and switched vote from an independent is twice as impactful as an extra vote. A simple example is you get one more of your base to turn out. You lose an independent, and you get 2 of their base to turn out. And end up down 3 votes.

Here's the study on turnout. And basically comes to the conclusion extremists motivate the opposing party base more than their own.

Here are a couple of journal articles.

https://www.cambridge.org/core/journals/american-political-s...

https://academic.oup.com/poq/advance-article-abstract/doi/10...

Note: There is small minority that show that this is effect shrinking with time. My personal belief for why this is happening is basically voters are judging individual politicians more by the moderation/extremeness of the party's positions and less by the politicians personal beliefs.

I'm confused. No one moved further from the center than Trump and it worked fantastically for hm.

Trump is one of the most moderate Republicans on most social issues (abortion, lgb, criminal justice etc.)

He is the most moderate on entitlements (constantly promises to not cut medicare, medicaid and social security) contrary to every Republican campaign in the past (remember Paul Ryan?)

He is a "moderate" on foreign policy (not a Cheney/Bush war hawk, not a 60's style pacifist)

I could go on but I think the important point is; every point he wants to make, he makes in the loudest most wild way possible and people who aren't disposed to vote for him anyway see that as "radical". The correct word IMO is "crazy" or "wild".

Voters who are in the center or can swing either way see him as promising fairly conventional things but in a crazy tone. Maybe tone doesn't matter as much to them

Which is hogwash, because at the time Trump went along with the Iraq war just like everybody else, of course:

   In the interview, which took place on Sept. 11, 2002, Stern asked Trump directly if he was for invading Iraq.

   "Yeah, I guess so," Trump responded. "I wish the first time it was done correctly."

So actually, um yeah, he was a "Cheney/Bush war hawk" just like the rest of them.

I have no idea if they edited this in later or you removed it but just pointing this out: > not a 60's style pacifist