In 2016, one of Trump's biggest mistakes (going by the national polling average, which is kind of questionable but whatever) was skipping the pre-Iowa debate, which caused him to lose ground in the polls and
if you think Iowa moved concurrently with the nation might've caused Cruz to win IA; if Trump had won that state he might've wrapped the nomination up on Super Tuesday. IA historically doesn't move with the nation -- see the outright Buttigieg victory there -- but who knows. (Trump
mostly did fine in the debates, but no debate really ever caused a surge of support for him. The only candidate to successfully attack him in a debate in a way that caused polls to shift was Fiorina in the second one -- yes, really -- but that was fairly quickly reversed by events.)
By percentage of the electorate watching them, debates mattered more for 2012-R and 2016-R than they did for 2020-D (and the much greater importance of caucus states on the GOP side means that we're probably underestimating this if anything), and the idea that caucusgoers
won't watch debates if Trump isn't in them seems strange; they did watch the fairly sedate 2012 field, and interest in politics is broadly higher today. (Attacking Trump would also be easier if he's not there; it's not like any of these guys would go out of their way to defend him.)
(Del Tachi has a point that not debating would be
poison with "people who always turn out in congressional/gubernatorial GOP primaries", but then a substantial part of the logic of a Trump bid is that he could turn out an unusual electorate, and some of that electorate even came out for congressional/gubernatorial primaries in 2022.)
Disagree. Debating those idiots doesn't run risk for Trump directly, but it does have a serious indirect downside: hours of footage of Trump having to stand next to Mike Pence as Mike Pence says the most unpopular stuff imaginable about abortion and asks if Trump agrees with him. Pence droning on about abortion for hours will make everyone in proximity to it look bad by relation.
I don't think it runs a
large risk, but the sheer fact that Fiorina could get a hit on him suggests it runs at least a small one. Saying more has to wait until we know what the qualifications to get in are; one of the most obvious differences is that this time around you will have candidates (at least Hutchinson, perhaps more) who are in the race substantially in order to kamikaze Trump at debates. I don't think that's a dynamic that's ever existed before at the national level and it's tough to see how it would play out.
