The Libyan war gave us the doctrine of “leading from behind.” Now, in Syria, we are about to see the birth of a new Obama Doctrine: military action “just muscular enough not to get mocked.”

That’s how one U.S. official described President Obama’s plans for a strike against the Assad regime. This is far worse than leading from behind. At least in Libya, Obama’s reluctant intervention led to the toppling of the dictator. In Syria, administration officials say their goal is to strike the regime without dramatically altering the country’s balance of power. This is nonsensical. The very purpose of military action is to “alter the balance of power” in a conflict. If that is not your objective, you should not use military power.

So what is Obama’s objective in Syria? In an interview with PBS, Obama said it would be to fire a “shot across the bow” of the Syrian regime. Huh? A “shot across the bow” is a warning shot. It is designed to send a message that a far more devastating response will follow if the target does not alter its behavior. But Obama has already ruled out broader military action. “I have no interest in any kind of open-ended conflict in Syria,” he said last week. “I assure you nobody ends up being more war-weary than me.”

In other words, he’s just planning to blow some stuff up.

Maybe that’s why Obama has not been able to build a coalition to join him in Syria. It seems no one (save the French) wants to participate in an attack “just muscular enough not to get mocked.” NATO Secretary General Anders Fogh Rasmussen said he sees “no NATO role in an international reaction to the [Syrian] regime.” The British Parliament has rejected the use of force in Syria. None of the Middle Eastern nations seeking to overthrow Syrian President Bashar al-Assad are backing Obama either, because, as The Post reported this weekend, they are concerned that “limited strikes could actually work in Assad’s favor.”

They are right. When you say that your objective is to do just enough “not to get mocked,” you are projecting weakness — and weakness is provocative.

It’s not just the Assad regime that is watching our response. Al-Qaeda is watching. Hamas is watching. Hezbollah is watching. North Korea is watching. China is watching. So is Iran. Let’s not forget that Syria is not the only place where Obama has drawn a “red line” on weapons of mass destruction. In Jerusalem this year, the president declared that America would “do what we must to prevent a nuclear Iran.” Why should the mullahs in Tehran worry about crossing Obama’s red line on WMDs when they see the Syrians cross Obama’s red line on WMDs — and the president’s reaction is to do as little as he can without getting mocked?

It is true that U.S. credibility is at stake given Obama’s red line on Syria’s use of chemical weapons. But the purposefully weak response Obama is planning — one he has telegraphed weeks in advance, allowing the Assad regime to move assets out of harm’s way — will do nothing to salvage U.S. credibility. Quite the opposite: A “shot across the bow” could embolden every potential adversary who might consider testing America’s resolve on the world stage. It could produce blowback in ways we cannot imagine — and in ways that may not be related to Syria.

Obama has asked Congress to authorize the use of force in Syria because he wants Republicans to share responsibility for the outcome. Fair enough. Now members of Congress should demand that Obama show he has a plan beyond firing a “shot across the bow” in Syria — a comprehensive strategy to alter the balance of power by strengthening the secular, moderate pro-Western elements of the opposition so that al-Qaeda-backed Islamic extremists do not come to power and the regime that eventually replaces Assad’s is not even worse.

If Obama can’t or won’t — if all he plans to do is (in President George W. Bush’s immortal words) “fire a $2 million missile into a $10 empty tent and hit a camel in the butt” — then Congress should refuse to endorse a feckless, symbolic strike in Syria.

“Leading from behind” was bad enough. “Just muscular enough not to get mocked” will embolden our enemies, weaken our security and make the United States the world’s laughing stock.

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