An attack on Iran would kill a number of civilians, embolden the Islamic extremists, raise the price of oil, threaten to reverse the progress American efforts have made in Iraq, bring retaliation upon the attackers and their enablers, , open the door to a major war, America on a collision course with China and Russia and possibly destabilize certain mideast nations. In favor of an attack is the possibility that an attack would delay Iran's nuclear program. Israel is the main cheerleader for making such an attack, but then Israel will be shielded by America from most consequences. Israel has gotten used to America acting as their umbrella. Israelis need a major dose of reality.
Military police vehicle attacked by rioters overnight in ultra-Orthodox area of Ashdod (Haaretz)
from the article: NATO official: Soon, Israel won’t have unanimous support for Iran strike