They act as if Buchanan could have single handedly prevented the civil war, I think that's ridiculous. Probably the same with most of the rest of these "errors".
I hate it when people expect other people to be like God, all knowing, again, ridiculous.
I'm not surprised that what I consider the worst presidential decision of the last 30 years isn't there:
Jimmy Carter decides to let the Shah of Iran fall.
As if the Civil War hadn't been building since before the United States even existed as a country. Or as if Buchanan could have changed Taney's insane reasoning in Scott v. Sandford, written before he even became President. It is ridiculous.
But sadly for these "historians" it isn't even the stupidest thing on the list.
In 1874, in Texas, the Republican government in Texas was voted out of office. E. J. Davis, the Republican candidate and sitting governor, refused to leave office. Richard Coke, the newly elected Democrat governor, and the new state legislature barricaded themselves on one floor of the capital, while Davis and his contingent barricaded themselves on another, asking for an armed military intervention from the US government to keep them in power. President Grant refused.
The author makes the fatal mistake of looking at history through current lenses, and fails to recognize the political realities of the times. The south instituted guerilla warfare (Klan), and the Union did not have the resolve to maintain a standing army in the south. They wanted out, so they declared victory and left. Slavery was dead, and the Southern states were still in the Union, but the North did not have the ability or desire to enforce change beyond that.
Buchanan was as bad as it gets and he could have done a hell of a lot beginning with not having a cabinet controlled by Slavers.