By Trump's own words, he is a "regime change" candidate. I refer you to his "closing ad," just posted: https://ckmacleod.com/2016/11/05/donald-trumps-argument-america-youtube/ That he and his words are not to be taken seriously makes him an unconvincing regime change candidate in his own right, but supporters like Decius and McCarthy, or campaign CEO Bannon, continue to argue that the regime such as it is deserves to be changed, that, at minimum, Trump represents both a statement and some practical movement toward the regime change they seek. As I stated, I consider their embrace of this position, or the form of their argument, a "minor" irony. It centers on a set of stances they adopt. One need not accept any of their arguments to observe that the latter are mutually contradictory.
As for my "negative stance" toward Trump, I have explained it many times and in different ways. I find Trumpism itself incompatible with the precepts of a liberal democratic regime. To the extent Trumpism succeeds, liberal democracy in the United States fails. To me, it is in no way surprising that this threat manifests itself in a particularly loathsome individual. I find it somewhat dismaying that a much larger number of people don't from within a few seconds of exposure to him recognize his utter unfitness for any position of public trust at all, much less the presidency. Many may not take him or the election, or the public statement of support for him, very seriously, or they may treat other notions about the meaning of politics, political choice, political speech, and so on, as more important. In other words, a partisan Republican convinced that Trump will likely lose, or unconvinced that the presidency matters very much or ought to, might endorse (vote for) Trump for any number of reasons that do not equate with support for Trump in particular. That goes for the Decius-McCarthy type of supporter as well as for the conventional "hack" supporters - Rubio, Cruz, Priebus et al - who seem to support "the effect of relative Trump success," not Trump himself. In that group may be many who hope, adapting Jonathan Chait's formulation, to achieve libertarian ends by more or less authoritarian means, even if the former have relatively little to do with anything Trump himself has advocated (setting aside his customary inconsistencies).
If my opposition seems too much a "passion" than a "sober analysis" to someone who signs his comments "Build the Wall - Kill em All," it's a cross I'll have to bear. I also am happy to leave final judgment to the Symparanekromenoi or to history.
Though I might dispute that Clinton ever qualified as a "major proponent" of Operation Iraqi Freedom, the only mention of her in the post was by "Decius." I don't believe that I, in observing the irony of the anti-Neocons embracing a "regime change" thesis, only for us rather than for the poor Iraqis, embraced the fallacy that the dubiousness of an argument for Trump must amount to a positive argument for his opponent.
I also don't think that "couldn't be worse" is something "only speculatively... imputed" to Trump supporters. I referred to Trump's own many statements of that type, which would be easy to document (e.g., his infamous, repeated "What have you got to lose?" during his African American "outreach" phase), and I quoted McCarthy and Decius. I could have added numerous other examples, drawn from twitter mentions, interviews at Trump rallies, or even exchanges at this blog with Tim Kowal some months ago.
As for a President HRC's likely foreign and military policy, I'd guess it would be informed by the Iraq War experience in toto, just as her support for the 2002 AUMF appears to have been informed by prior experience. As you may recall, I don't personally choose to participate in the "well-night universal consensus or groupthink" either on the war decision or on the assumption that the counterfactual, no invasion in '03, would certainly have produced a "better" outcome.
All the same, I do think that the faultiness of the double last resort Trump argument - last resort argument for Trump, Trumpism itself as a last resort - since it is offered after stipulation to Trump and his movement's otherwise disqualifying flaws, leaves us with the debater's, or conservative's, presumption of the status quo, which is best represented by the Democratic candidate in this cycle.
The argument for Trump is put as a "regime change" argument. I don't see much from the Trumpists resembling a practical or considered or even minimally responsible or even minimally credible or cogent plan for the new regime, or for coping intelligently with the much more likely result of the old regime's continuation.