@voltronic I believe that the initial hold up was two fold.
The first HIMARS vehicles delivered did not have ATACMS capability (at the request of the original purchasing nation). Later HIMARS vehicle deliveries did have that capability and are what led me to consider ATACMS as a possibility for the first Kerch bridge attack.
I suspect that the later hold up was more about US ATACMS inventory being low than about Ukraine attacking Russia (which it has done several times since the war started).
@Render
In other words, I'm agreeing with you that supposed a red line doesn't seem to exist or at least we haven't seen one yet. So if it's not a supply issue, then why not give UKR the capability to hit harder and farther?
The only thing Putin can do that's worse than what he's doing is nuclear, chemical, or biological. And he knows that NATO will become directly involved if he goes there.