I’m thinking he kept some PDBs that had either nuclear asset postures or something similar for a potential event like China invading Taiwan, or Russia invading Crimea/Ukraine. I doubt he pulled nuclear weapon plans or anything of the like because that would have raised red flags when it happened because 1) those documents don’t reside in the WH, 2) there would be a paper trail for the request, courier, logging out of one SCIF into another for storage, etc, and 3) the pentagon/archives would have definitely noticed that they weren’t returned at the end of his tenure.
it doesn’t make it any better, our most dangerous secrets are generally pretty benign looking stuff. Asset postures give adversaries a peak into how we would prosecute a major shooting war. I’m sure his PDBs contain lots of vulnerability assessments for things like our energy grid, cyber, troop readiness during Covid, nuclear weapon and fleet assessments, etc that would provide avenues to exploit.
My best guess is a USSS agent saw Trump showing off something like a PDB to donors/hangers on that contained sensitive material and blew the whistle. The ugly part is that if it’s truly sensitive the gov’t won’t be able to really talk about it because “we cant confirm or deny” is the only valid response you can use to anyone that doesn’t have the clearance and need to know about the info, so he can exploit that soft language. There will be committees in congress that will be able to get the truth, and I fully expect the Rs on those committees to use similar dodgy language or just outright lie to prove cover for that orange fuck.