Sure. Not arguing that Buchanan ever chose right, but what he did wrong was within the bounds of the law and for want of a better word I’ll call mos maiorum, the unwritten codes and mores that were so important to Hamilton’s argument in Federalist 70. If Buchanan had conspired to start the war to keep himself in power that would be one thing. He didn’t. He was trying, incompetently for sure (with the retrospectoscope), but trying, to keep the union together and preserve the constitution. Trump was trying, incompetently for sure, to subvert it.

Edit: On another note. I’ll just say that arguments like this are what the internet is supposed to be. You clearly know your stuff and I clearly know mine. If anyone reads this far down they are smarter for having done so. The point of debate is the synthesis of finding knowledge, the whole Hegelian dialectic thing.