[Goose]

So the US just had a lucky hunch Russia was going to proceed. In any case, whether it was a lucky hunch or not (very much doubt it was), I think it helped.
Consider the counterfactual, does it help the US and Ukraine more for us to have said nothing in the lead up? Should we have not warned about possible chemical weapons usage?

Exactly!! It was by definition a "lucky hunch". Putin could have just done nothing. Even if we thought it probable his definite intention was to invade, he could have changed his mind for any reason or no reason. We did exactly what you suggest. We considered the counterfactual. It cost us little or nothing to say what we said and warn about chemical weapons. We also contacted Ukraine and established a way forward if Putin did move. If we were wrong, worst case it creates a "cry wolf" possibility next time. Not doing so risked a totally delayed response, too little and way too late. In fact, I would argue that even if on the balance we thought Putin WASN'T going to invade, we would/should have done exactly the same thing. Little risk, great benefit. It is always better to have a plan you don't need than to urgently need one you don't have.

Ukraine, FWIW, was saying that "The Russian's aren't coming". Did they actually believe that? IMHO, probably not. They just wanted to keep their economy from tanking any sooner than necessary. What nations say and what their intelligence assessment says are almost always at odds, sometimes more, sometimes less.

I don't think it's a surprise to the Russians that the US is giving Intel to Ukraine, Russia doesn't need any more help to drive their rhetoric since their domestic audience is captive to lying state media anyway, and what has been disclosed doesn't sacrifice any human sources. So I only see upside.

Agree no human sources at risk. Confirming that belief is still a bad idea though. In GRU headquarters there is always the nagging doubt "Does Ukraine have an active source inside Black Sea Fleet planning?". Mitigating that doubt is never a good thing, unless, of course, they do.

[Goose]

So the US just had a lucky hunch Russia was going to proceed. In any case, whether it was a lucky hunch or not (very much doubt it was), I think it helped.
Consider the counterfactual, does it help the US and Ukraine more for us to have said nothing in the lead up? Should we have not warned about possible chemical weapons usage?

Exactly!! It was by definition a "lucky hunch". Putin could have just done nothing. Even if we thought it probable his definite intention was to invade, he could have changed his mind for any reason or no reason. We did exactly what you suggest. We considered the counterfactual. It cost us little or nothing to say what we said and warn about chemical weapons. We also contacted Ukraine and established a way forward if Putin did move. If we were wrong, worst case it creates a "cry wolf" possibility next time. Not doing so risked a totally delayed response, too little and way too late. In fact, I would argue that even if on the balance we thought Putin WASN'T going to invade, we would/should have done exactly the same thing. Little risk, great benefit. It is always better to have a plan you don't need than to urgently need one you don't have.

Ukraine, FWIW, was saying that "The Russian's aren't coming". Did they actually believe that? IMHO, probably not. They just wanted to keep their economy from tanking any sooner than necessary. What nations say and what their intelligence assessment says are almost always at odds, sometimes more, sometimes less.

I don't think it's a surprise to the Russians that the US is giving Intel to Ukraine, Russia doesn't need any more help to drive their rhetoric since their domestic audience is captive to lying state media anyway, and what has been disclosed doesn't sacrifice any human sources. So I only see upside.

Agree no human sources at risk. Confirming that belief is still a bad idea though. In GRU headquarters there is always the nagging doubt "Does Ukraine have an active source inside Black Sea Fleet planning?". Mitigating that doubt is never a good thing, unless, of course, they do.