We have seen exactly zero indications that the republicans might start nominating better candidates anytime soon. The next candidate will probably be "Trump, but less incompetent at implementing his agenda". It makes sense to want to stall as long as possible, but needing a democrat victory every single election from here out is not going to be a winning strategy longterm. If Trump winning is guaranteed global chaos, then there aren't votes we can cast that will do anything other than slightly delay that.