It is four parts. I just listened to part one today. What do you think?
More to the point, what resources can I find to back up her story?
[Moderating]
I think this might have been intended for a different thread, or for a private message? As-is, it doesn’t seem to make much sense: Maddow surely has a lot more than four podcast-parts in total, and what story are you looking for backup on?
If there’s more here that you want to add, let me know.
My apologies; I hadn’t realized that “Ultra” was the name of her current podcast, which led me to misparse the OP: I thought that it was a question addressed to Ultra (UltraVires? Though I haven’t seen him around much lately), and without knowing that it was about a specific series, the question seemed impossibly vague.
A couple of other posters explained the situation to me, so we’re fine. Though one might still ask which specific details you want backup for.
I’ve listened to the first two episodes so far. I found it to be interesting, and details things I wasn’t aware of, though I knew about, generally, the America First movement prior to the U.S.'s entry into WWII.
As far as Ernest Lundeen, the senator from Minnesota who was the focus of the first episode, it’s pretty easy to find similar, corroborating information online. As Maddow says in the podcast, the cause of the plane crash was apparently never definitively determined.
Here’s an article about Lundeen, and the plane crash; it also does corroborate that there were FBI personnel on the plane.
Here’s a 2010 opinion piece from a Minnesota newspaper: a cautionary tale about Lundeen, which also mentions Lundeen’s secretary, who quoted Lundeen as saying he’d “gone too far,” immediately prior to the crash (Maddow provided similar quotes):
Here’s an archived 1942 article from Time Magazine, about the Nazi propagandist who had been working with Lundeen, as well as with another Congressman, Hamilton Fish of New York:
And, this link has photographs of the pro-Germany speech which Lundeen had with him when his plane crashed:
https://www.documentcloud.org/documents/23127861-lundeen-germany-speech_sm
Her podcasts have been excellent.
So much changes, so much stays the same. This century is echoing the last.
I’ve heard her give short descriptions of the topics. Frankly, those descriptions give me the willies considering the current political situation. I’m afraid the podcast would give me nightmares.
I really like how she maps things out though, so I’m going to try and put on my big chick drawers and listen to her. 
And it echoes Karl Marx’s pamphlet, The 18th Brumaire of Louis Bonaparte: “Hegel remarks somewhere that all great world-historic facts and personages appear, so to speak, twice. He forgot to add: the first time as tragedy, the second time as farce.”
Amazon has no biography of Senator Lundeen. Probably none was ever published. I have not looked for the CAA accident report. What easily-accessible documents provide further background to the story told in this podcast?
Each episode has archival materials up on the podcast website at MSNBC.
Thank you. Yes, I know.
This is Lundeen’s biographical page on the Minnesota Legislature website. Not a lot of information there, though it notes (and there’s a link to a short article about it at the bottom of the page) that he ran for either state or federal office sixteen times, losing in ten of those elections.
I look forward to each segment. Will be interesting to see where she takes this.
Here’s an article in Slate about Father Charles Coughlin, the Roman Catholic priest in suburban Detroit who’s extensively mentioned in episode 2 of “Ultra.” His 1930s radio program was originally rather progressive, but it became increasingly extremist and anti-Semitic as Coughlin’s anti-Communist sentiments evolved into pro-fascism, until the show was finally forced off the air.
https://slate.com/technology/2021/01/father-coughlin-deplatforming-radio-social-media.html
When I listened to that episode, I wondered to myself about how a Catholic priest was able to get away with that level of public hatred for so long, without censure from the church hierarchy. The Wikipedia article on Coughlin says this: