In pure amoral military terms, the US military has barely suffered a scratch in this war, losing only a few soldiers and pieces of equipment. It has failed to subdue Iran, so in that sense so far at least it has not achieved a victory. However, it has also not suffered a defeat. If the Iranian government ends the war still in power and with the ability to keep the Strait of Hormuz closed whenever they want to, I will consider that a a US defeat. However, the defeat would not have been caused by any serious damage that Iran has done to the US military, it would have been caused by the combination of Iranian resilience to damage and its geographic advantage of being right next to the Strait of Hormuz.