In essence, there's no sane logical reason for defending Trump and his behavior. The only recourse for any reasonable conservative to take is to incessantly attack Hillary and completely ignore Trump's outrageous musings.
Well, that's all good for them as the GOP's tactics are well honed and time tested in this regard. However, what you end up with is comparable to flogging the proverbial dead horse, especially in Hillary's case as the GOP has been at her throat for decades and that engine has run out of steam. Their looped message of Hillary hate has become plain old white noise except to the nutjob base of the party, who, IMO, really do not represent the majority of the party that constitute a body of sane Repubs who see things in the here and now.
Bottom line, the reality that the Repubs face is the fact that Trump's negatives far outweigh Hillary's, and without doubt, Hillary's positives outweigh Trump's in the way of qualifications.
IOW, there's hardly any angle of attack that will bring Hillary's numbers down to a point where Trump will appear to have a reasonable chance of winning, so why even try?
If I were a sane reasoning conservative, it would seem impractical to argue in Trump's favor and if pursued, will only result in suffering from the appearance of being a Trump fanatic with no other purpose but to stoke the fires of Hillary hate.
That's my guess, as seen from the outside in.