If Israel were to attack Iran, that would be the end of her. She will have given up her ability, if not her 'right' (if there is any such thing), to exist by her own actions. The US military is already stretched as thin as it can be, and any Israeli action would have to take place over and through the US presence in Iraq. This would lead to Iran retaliating on Israel through Iraq, thereby directly involving the US again. Numerical superority would give the Iranians a strategic advantage on the ground, and when that is played out there will be no more shield for Israel. Israel will also lose all political support as the American people will not stand for Israel choosing more death for our boys through their inability to come to peace with its neighbors.
Magnitude 4.2 quake strikes near Grand Coulee Dam in Washington (Reuters)
from the article: Report: Washington concerned Israel gearing up to attack Iran