Not sure this counts as a 'societal collapse' issue, but perhaps...
On vacation in CA and reading a few books. One I highly recommend is "Nuclear War: A Scenario". (Yeah, yeah, I know, kind of crazy book to read on vacation.) The author, Annie Jacobsen, interviewed about 50 people who are most knowledgable about the US's nuclear war plans and responses, including military & Administration insiders, down to the finest detail. Even tho I've been around this issue a bit for 40 years, the response process is far more complicated than I imagined. The author lays out a very credible, minute by minute scenario of one scenario which is possible. It's sobering, partly because of how little the person who makes the final decisions (the US President) is aware of the details of the process, and the virtually zero time frame in which to make potentially 'end of the world' decisions. It's a page-turner, and very educational. I'm halfway through the book, and at this point, the person tentatively in the line of succession to make those final decisions is the Sec. of Defense. Think about who that would be today.