For a man who ran as the anti-war candidate, President Obama sure is trigger-happy.

We’re now in our third war in the Middle East, and if the rationale for the Libyan War is a guide, it may not stop there. President Obama has opened up a whole new line of work for the U.S. military – to intervene in other countries’ civil wars to protect their citizens from their leaders. But not to worry… he’s going to do it in a limited way – limited mission, limited use of force, limited role in a coalition. No ground troops, hence no U.S. casualties.

But war isn’t a game where you get to kill enemies on a computer screen but don’t have to suffer losses yourself. Real war isn’t clean or neat or over quickly. The fundamental rule of warfare: is things NEVER go as you planned, you have to expect the unexpected. That’s why we have to be clear about both the military and political missions before we go in. They’re bound to change once the real war begins. If you don’t know where you’re headed before you set out, you’ll never know when you’ve arrived.

Both of those missions are muddled with the Libyan. What’s the military goal? To kill Qaddafi? To leave Qaddafi in power but force him to stop killing his people? To back up the rebels so they can defeat Qaddafi on their own? Who’s fighting with us, and who is calling the shots? President Obama? The French? The British? The Pentagon? Secretary Clinton? And by the way, what ever happened to the Arab League? They initially backed a no-fly zone, but are having second thoughts now that people are getting killed. What if Qaddafi escapes to fight a prolonged insurgency?

Even if we succeed militarily, what is the political objective? To turn Libya over to the rebels? We don’t even know who the rebels are! They’re not unified or battle ready. They may be committed, but at this point they’re not capable. Could we live with a two state solution? 

Defense Secretary Gates says we will hand over operations in a few days. But to whom? NATO? Alliance member Turkey, was against the Libyan operation from the start. The French? The British? The Arab League? 

We learned with Afghanistan and Iraq that the military operation is the easy part, it’s what comes next that’s hard. If you decapitate the government, who’s in charge of running the country? At some point somebody has to put boots on the ground if for no other reason than to facilitate a transition.

But there’s an even bigger problem with the Obama Doctrine; the precedent it sets. There are a dozen countries where leaders are slaughtering their own people, and we can’t insert ourselves in all of them. More people have died in Yemen than Libya. Iran routinely arrests and executes its dissidents. Sudan is committing genocide. What about Syria? Bahrain? Ivory Coast? Does the Obama Doctrine mean we should intervene in all of them as long as we do it in a limited way and not send in ground forces?

When I was in the Reagan administration, I drafted Defense Secretary Weinberger’s Principles of War Speech, which outlined the criteria the U.S. should use when committing combat forces abroad. After 241 US Marines were killed in their Beirut barracks by a suicide bomber in October 1983, some in the Reagan Administration wanted to go put more forces into the region, to insert ourselves in to the middle of the Lebanese civil war. Sound familiar?

The military were skeptical, as was Defense Secretary Weinberger. I was Weinberger’s speechwriter, and he asked me to go around the Pentagon and pick the brains of the top brass, the men who had been junior officers in Vietnam. I took their lessons learned and drafted a speech which ultimately became the Weinberger Doctrine; which served as the principle governing use of combat forces abroad throughout the Reagan years. It was later expanded in the Bush administration, with the first Iraq War, and known as the Powell Doctrine.

The Weinberger Doctrine stipulated:

1) We should commit combat forces overseas only in support of a vital American national interest.
2) If we did so, we should do wholeheartedly, with the clear intention of winning.
3) We should have clearly defined military and political objectives going in.
4) Those objectives and forces required to achieve them should be constantly reassessed and adjusted, to avoid mission creep.
5) We should have the support of the American people and their elected representatives in Congress and be up front about the length and cost of our efforts.
6) We should commit combat forces only as a last resort.

Critics at the time said the Weinberger Doctrine was too limiting. After September 11, the Bush administration discarded it for a doctrine of preemptive war, arguing we needed to fight terrorists abroad so we didn’t have to fight them at home. Fair enough. Every president gets his own military doctrine….until the next president comes along.

And now, nearly a decade later, we’re still in Afghanistan and Iraq, and President Obama has launched a third Middle East War. With it he’s launched the Obama Doctrine – limited war in foreign lands to protect slaughter of the innocents by their own leader. It’s a noble goal. But is it a vital U.S. interest?

Libya’s oil may be a vital interest to France, Britain and Italy. All of Europe may be concerned that a flood of Libyan refugees will arrive on their shores at a time when they’re economically challenged. But Libya is not something we would define as a core American interest.

America’s core interest in the region is the free flow of oil through the Strait of Hormuz and the stability of the Arabian Peninsula. If we’re tied down in Iraq and Afghanistan and now in Libya, will we have the resources necessary to deal with crises in the Gulf should they arise?

Maybe everything will go right in the Libyan War, and Qaddafi will be toppled, the rebels form a government, and our troops can come home. But the job of military planners is to plan for the worst, not the best case scenarios. And the worst case scenario for Libya is not a pretty sight.

It’s time somebody took the Weinberger Doctrine off the shelf and dusted if off. Limiting the wars we fight rather than fighting limited wars is starting to look good again.

Kathleen Troia "K.T." McFarland is a Fox News National Security Analyst and host of FoxNews.com's DefCon 3. She is a Distinguished Adviser to the Foundation for the Defense of Democracies and served in national security posts in the Nixon, Ford and Reagan administrations. She wrote Secretary of Defense Weinberger’s November 1984 "Principles of War Speech" which laid out the Weinberger Doctrine. Be sure to watch "K.T." every Monday at 10 a.m. ET on FoxNews.com's "DefCon3" already one of the Web's most watched national security programs.