My reading is the benefits start at 10% of BW and go up from there. Rucking was part of my workout a few years back. I started at 10% and added weight as I adapted. I wanted a 60 min walk to be tough and added weight as needed to do that. No idea how high I got.
(Saying this in jest.)
Rucking had it's run, but has now jumped the shark. I saw a >65 yo lady on the trail yesterday wearing a weight vest. Not one of those faux body armor cosplay weight vests, but one with cast iron wieights. Looked like she had it loaded up good. From age 35 to our inevitable death, all we do is try to outrun in. In here case, she's taking joint health and osteoporosis for serious. Good for her.
That said, the youngs are gonna hafta look elsewhere. I predict jazzercise is gonna make a comeback.
Russia thinks they need all these buffers because they make it harder to get invaded. That's true. You know whet else makes it harder to get invaded?
Don't spend >200 years being an asshole to everyone in the World. Be a model citizen and people will seek out your friendship, and not takes steps to protect themselves from your assholishness (NATO).
The US providing all the satellite intel, logistic support and willing to sell any and all 2nd-line kickass American weapons they want, is a winner. This IS happening in Europe and it's entirely fair to tell them we won't put our own people in direct danger.
ETA
And for Pete's sake already. We can sell BILLIONS of dollars of high-end American weapons to these guys. Exports. Jobs. Trade balance. And if a few Russians die in the process oh well.