I finished that 170,000 word behemoth of a TL a month or two ago and I loved every bit. By the last third or so it had become like one of those 1970s exploitation film, except with totalitarian dictatorship being turned up to 11 rather than sex or violence. Every single chapter I thought “they can’t possibly make it worse” and they found a way, every single time. I think at the beginning he was trying to legitimately explore the idea of the US being Balkanized, with soomewhat of an edgy tone to it, as shown in the descriptions of Hamilton’s execution and George IV’s insanity. But by the 1930s it had essentially lost all contact with plausibility and rationality, and it was awesome. WMIT was dark, twisted, demented and entertaining as hell. I highly recommend it.
One other thing I want to mention about What Madness is This (I know this isn't the thread for it, but I just wanted to say it) is that the authors did a great job of creating a dark historical doppelganger of the USA. The Republican Union's history mirrors that of America in many ways, but with America's historical good qualities practically nonexistent and its bad qualities cranked way out of proportion. For example, IOTL, when the US did not lose the War of 1812, it led to the country developing a strong, yet mostly benign, sense of patriotism and nationalistic pride. In WMIT, the ATL-War of 1812 (which results in the RU being invaded and overrun) generates a very different national reaction: namely, it gives the RU a nasty revanchist and expansionistic streak that leads it to annex a peaceful and defenseless neighbor just 20 years later for no reason, and it all goes downhill from there.
Another example: When immigrants from Germany and Ireland came to America in the 1840s and 1850s, they were drawn mostly by (somewhat exaggerated) tales of economic opportunity and determining one's own destiny. Typically these immigrants were simply plunged back into poverty, but a large number were still able to find success as farmers or factory foremen. Anti-immigrant sentiment rose in the form of Nativism but never really became a mainstream political force. Whereas in WMIT, agents of the RU are instructed to straight-up lie to potential immigrants in Eastern Europe; when they come to the RU, hoping to find freedom and opportunity, these immigrants are forced, one and all, into slave-like labor and given no rights, because anti-immigrant sentiment and racism have become the institutionalized law.
Now let's move on to Manifest Destiny. IOTL, this was the doctrine that led the U.S. to essentially commit genocide on the Native Americans for the sake of taking over what is now the lower 48--clearly one of the US's most villainous and despicable actions. In WMIT, RU uses manifest destiny as an excuse to take over the entire Western Hemisphere and exterminate the locals concentration camp-style. And one final comparison: ask an American what the best thing about America is, and chances are they'll say freedom--because it's constantly banged into out heads that we're a free country. But no matter its purposes in such nationalistic rhetoric, it's true--America is a free country in the sense of such things as freedom of speech, freedom of enterprise, etc. By the mid-nineteenth century, the Republican Union can't seem to shut up about its own freedom--despite the fact that by that point there is literally no freedom anywhere in the empire.