Iran has been killing American soldiers in Iraq and Afganistan for years with O response.
We sit and do little but wring our hands.
That is largely true when it comes to “up front” confrontation, but “black ops” is not just a video game for kids, they really happen. The military is a complex beast with many different heads yearning to push, pull or prod itself in different directions. A few things I can guess at....
There are parts of the military ready to respond in the event that Israel and Iran go “hot”.
There are parts of the military/political leadership that is prepared for “plausible deniability” if some things go South.
Most of what goes on, though, is kept from most of us through subtrifuge and smoke.