

This isn’t a language issue. The two forms I’m contrasting use the same definition of “could.” But there is a world of difference between:
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A scenario which is uncertain, but real information indicates there is a decent chance of happening. (The “could” used in the article.)
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A scenario which theoretically could happen, but is unlikely and there is no particular evidence available that the scenario is likely. (The “could” you’re using in your hypothetical about Russia disintegrating.)
An infinite number of things are theoretically possible. The article isn’t some baseless speculation saying, “hypothetically, there’s nothing in the laws of physics preventing Russia from invading NATO.” The article is instead saying, “while the intelligence is still uncertain, intelligence indicates a substantial probability of Russia invading NATO territory.”
It’s an issue of probability. The article is probably talking about a scenario with a 30% chance of happening in the next year, a scenario that has real evidence suggesting it’s likely in the near-term. You’re raising a scenario that probably has less than a 1% chance of occurring in the next year, one backed by pure speculation with no evidence at all behind it.
Intelligence is never certain. That doesn’t mean it’s useless.



The opposite could also happen. Countries facing direct threats to their own territory are less able to provide military aid.