An oil-rich tyrant with a history of sponsoring terrorism is now "brutalizing his own people." All that is needed to stop the violence is the limited use of Western military might.

Haven't we heard this story before?

While Libya differs greatly from Iraq, it nonetheless reminds us how much easier it is to enter a conflict than exit one. This week, President Obama and British Prime Minister David Cameron agreed that "the full spectrum of possible responses" was on the table. Among these options, two military proposals, a no-fly zone and arms for the rebels, appear to be gaining the most attention on Capitol Hill.

At this stage in the conflict, the Obama administration is to be commended for exercising caution. This hesitance is not a sign of weakness, but reflects careful consideration of the preconditions for committing American military forces to an international conflict.

We believe the best set of guidelines for deciding when to commit our troops to foreign wars rests in the Powell-Weinberger Doctrine. Although not a codified document, the policy advocates military action only when vital national interests are at stake, when there are clearly defined political and military objectives; once all other diplomatic options have been exhausted; after developing a plausible exit strategy; and then only with an overwhelming force to ensure victory.

None of these critical questions have been sufficiently answered to justify intervention in Libya. As of this writing, troops loyal to Moammar Gadhafi have recaptured the strategic oil port of Ras Lanouf. In an effort to consolidate regional support, the experienced autocrat has dispatched an envoy to woo Egypt's military leaders. The momentum appears to have shifted back in favor of Gadhafi in what is quickly becoming a protracted civil war.

There is no indication that either a no-fly zone or providing arms to the rebels will represent the critical turning point in the conflict. According to the International Institute for Strategic Studies, a no-fly zone would have limited effectiveness in stopping Gadhafi's advances. Most of Libya's fighter jets are nonoperational, and its air superiority stems from 35 attack helicopters, which can evade the anti-aircraft measures of a no-fly zone.

Supporters of a no-fly zone have attempted to downplay its aggressiveness. However, Defense Secretary Robert Gates testified last week before Congress that a no-fly zone would require a preemptive strike against Libyan air defenses, thereby constituting an act of war.

We naturally have an inclination to support rebellions against dictators. Yet, it is reckless to arm anyone but a trusted ally. In the wrong hands, weapons could be used against our troops in other conflicts. As White House press secretary Jay Carney recently put it, "It would be premature to send a bunch of weapons to a P.O. Box in eastern Libya." The West's tenuous relationship with the rebels was further evidenced over the weekend, when British Special Forces were detained by the very Libyan rebels that they were sent to support.

U.S. intelligence agencies, which failed to predict recent uprisings, would be responsible for identifying our strategic allies. There are plenty of reasons to question whether they are up to the task. Sen. Dianne Feinstein, D-Calif., chair of the Senate Intelligence Committee, recently complained that intelligence reports have "nothing that we didn't read in the newspapers."

Finally, all diplomatic options have not run their course. Britain and France are moving forward with a U.N. resolution for an internationally sanctioned no-fly zone. Russia and China are expected to veto the measure, but such action has yet to occur. Given the questions large and small surrounding a military commitment — as columnist George Will noted this week, such action is premature.

REPRINTED FROM THE ORANGE COUNTY REGISTER.