Here's a Unique Concept: It's Only a Regional War if a Major Israeli City is Hit

Four times today, the most recent on Joe Scarborough on MSNBC before I could find the remote to turn him off, I've heard something quite similar to this:

x number of Israeli soldiers killed, x number of wounded in Israel, four bridges in Lebanon destroyed, 28 Lebanese farmers killed on a strike right at the border between Lebanon and Syria, a Hezbollah rocket hits 30 miles south of Tel Aviv...
BUT... if Hezbollah strikes Tel Aviv, this is going to be WAR, a BIG REGIONAL WAR where the U.S. will get involved on the side of the righteous: Israel

Um... hasn't it already been a war for more than 23 days? But only if it hurts a major Israeli city is this a bad thing although the city of Beirut and smaller cities in Lebanon are in ruins, with more than a million people displaced, and close to a thousand civilians dead there (compared to about five dozen Israelis). But hey, Tel Aviv is sacred so it's hands off?

I don't think I quite get this mentality. Israel has not only destoyed a sovereign nation, it has now breeched the border with Syria, an entirely different country. But that's fine. It's just when it hurts Israel that there is a problem. Then the U.S. will get involved because no one is allowed to touch Israel. Total insanity!