U.S. forces and facilities are more accessible than those of Israel. This could include terrorist attacks in Lebanon, Iraq, Saudi Arabia, and the smaller Gulf Arab states against any available American civilians, institutions, or soldiers. And the biggest front of all might be the Persian Gulf itself. Would small Iranian boats stage suicide operations to hit tankers or try to block traffic?
As happened in the latter phase of the Iran-Iraq war in the late 1980s, the Gulf Arab states would likely ask the United States, European countries, and NATO to convoy their tankers. A shooting war could lead to the dragging of the United States into a military conflict with Iran. Whatever happened on the ground (and water), the price of oil would skyrocket.
These factors also affect Israeli interests since that country would be blamed for the resulting carnage and disruptions. Antisemitism would increase and a lot of people would claim that Israel dragged America into an unnecessary war. Promises of quick, easy victory, the disappearance of any Iranian nuclear capability or threat, and even the fall of the Iranian regime would prove false, stirring bitter controversy.
There are, then, major dangers and real strategic problems in any campaign to attack Iranian nuclear installations, and they require serious thought and a rejection of recklessness. A war with Iran, if conducted at all, should only happen when it seems otherwise unavoidable. And that is far from true this year.
But that day will come and people better be psychologically ready for it.