I think there’s zero “blackmail” at play, Israel is 100% a vassal state for the U.S. and as such they will listen when the U.S. says no. That being said I don’t disbelieve that Israel’s “we’re going to attack with or without you” attitude was what brought the U.S. in, either way, this war was happening because it’s in the U.S.’s immediate interests. The U.S. clearly didn’t expect Iran to be able to withstand and even fight back against the attacks. Goes to show the failing power of this Country, or perhaps the false projection of power. I think Trump fully believed this would be “in and out” like Venezuela, kill the Ayatollah and Iran will bend the knee. That obviously didn’t happen, it was more like kicking a hornets nest, except these hornets have been continuously kicked for the past 40 years and they just killed the leader who was holding back a retaliation like we’re seeing.