It would be empty threats and Iran knows it. The USA can not afford yet another war because Irsael wants to maintain its aggressive hegemony in the ME. Americans do not support more soldiers dying for no good reason. This has nothing to do with the US. Why send our soldiers there to die ?
Jerusalem suburb of Even Sapir evacuated as wildfire spreads (Haaretz)
from the article: Netanyahu will ask Obama to threaten Iran strike