The US has two amphibious assault carriers as part of Fifth Fleet. The Johnny Reb is also part of Fifth Fleet at present. There are not many allied ships in the region at present. Reagan didn't back down from Gadhafi over Sidra. Why would Obama back down from Ahmadinerjacket?
Western-backed Syrian rebels say kill foreign Islamic State (Reuters)
from the article: Iran to hold another naval drill near Strait of Hormuz next month