So in the TL "The Falcon Cannot Hear", FDR is killed by Zangara like he almost was OTL. Later, due to his policies, Garner loses in 1936 to Alf Landon and due to how Landon handles the country, it slowly crumbles into a Civil War. However, given how that TL is over nine years old at this point and a lot more is known about Garner and Landon at this time (such as Garner being genuinely more receptive to New Deal ideas than the Timeline would suggest or Landon being generally pro-New Deal despite the relatively widespread idea that he was some arch-conservative), it makes the premise of how everything fell apart shaky, at best. On the question at large, if Garner becomes President on March 4th, 1933, is he likely to mess up the Presidency as he did in the aforementioned TL to the point of losing to Landon or a Republican in 1936? How would Landon do if he became President? Could something like what happened with the TL happen like it did or is it extremely unlikely?
In my humble opinion, you kinda need three factors for things to get as bad as it did in TFCH : 1) Zangara kills FDR, as what happened in the TL and Garner proves to be a mess (which I'm unsure of); 2) Huey Long isn't assassinated and thus can run third Party and has a great chance against Garner; 3) Instead of Landon, Have a more Conservative Republican like Newspaper Publisher Frank Knox be nominated and elected due to the vote split among the Democrats and even then, I find what happened in TFCH unlikely. Plausible under set circumstances, but extremely unlikely.
In my humble opinion, you kinda need three factors for things to get as bad as it did in TFCH : 1) Zangara kills FDR, as what happened in the TL and Garner proves to be a mess (which I'm unsure of); 2) Huey Long isn't assassinated and thus can run third Party and has a great chance against Garner; 3) Instead of Landon, Have a more Conservative Republican like Newspaper Publisher Frank Knox be nominated and elected due to the vote split among the Democrats and even then, I find what happened in TFCH unlikely. Plausible under set circumstances, but extremely unlikely.