After weeks of ambiguity, President Obama is starting -- but only starting -- to develop a policy on Libya that involves more than rhetoric. On Friday he issued an ultimatum to Moammar Gaddafi, telling the Libyan dictator that he must end his offensive on the rebel movement or else face international military intervention.

The president had already received criticism as he waited for the United Nations to confront the Libyan crisis. It finally did, passing a surprisingly strong resolution authorizing action Thursday, and Obama had the license he wanted to use real threats.

"Clear conditions must be met. A cease-fire must be implemented immediately....All attacks on civilians must stop....He [Gaddafi] must stop his advance on Benghazi...."

But if Gaddafi complies, digging into his stronghold in Tripoli? The president didn’t clarify would happen then.

Perhaps Obama simply doesn't think Gaddafi will accede to international demands. Obama poured skepticism on Gaddafi's promise of a cease fire: "There should be no doubt about his intentions. He himself has made them clear....He threatened, and I quote, 'We will have no mercy and no pity.' No mercy to his own citizens."

Or perhaps Obama does think Gaddafi will comply, and the administration would be happy to have more time with a cease fire in place to deal with the situation by other means.

Instead of exploring this question, the president focused on what would happen if Gaddafi ignored the ultimatum.

"These terms are not subject to negotiation. If Gaddafi does not comply with the resolution, the international community will impose consequences. And the resolution will be enforced through military action."

Those consequences could include tighter sanctions and a no-fly zone. But what about arming the rebels? Or offering incentives for Libyan military officers to defect? The president was clearer about what tools he has ruled out: "We will not put ground troops in Libya."

Obama also tried to allay fears of mission creep following direct American involvement: "We are not going to use force to go beyond a well-defined goal, specifically the protection of civilians in Libya." Where does "protection of civilians" end and, say, "regime change" begin? That language is still conveniently vague. As is what would happen if limited intervention doesn't prevent Gaddafi from brutally reasserting his power. And the critical issue of what a post-Gaddafi Libya would look like. The president has much lot more explaining to do as America gets more involved.