When the mission in Libya began, the President was clear that it would be measured in days and not weeks. Well, NATO has told us how many days. Apparently, about 90.

NATO has planned for a three-month no-fly operation over Libya, but could make it longer or shorter if necessary, an alliance official said on Friday of a mission that is due to start early next week.

The U.N.-mandated no-fly mission, approved by NATO states on Thursday, will involve dozens of planes from the 28-nation military alliance.

NATO spokeswoman Oana Lungescu said the alliance would decide “in coming days” whether to broaden its role to take over full command of military operations, including ground strikes to protect civilians, from a coalition led by France, the United States and Britain, which began air strikes almost a week ago.

In the meantime, she said, “the coalition operation will continue to put pressure on the Libyan regime.”

I mean, sure, you could call it three months, but it’s supposed to be measured in days, so I’m going with 90.

So far, 10 NATO members will fly planes in the mission, as well as two Arab members of the broader coalition, Qatar and the UAE. Canadian General Charles Bouchard will command the mission, NATO said, although one Group Captain claimed it would actually be U.S. Admiral Samuel Locklear.

More interestingly, despite the multiple assurances that NATO would take command of the mission, the talks are ongoing. “There have been differences of opinion about whether attacks on ground troops should form part of the action,” according to the BBC, suggesting that the scope of the mission has not even been determined. Steven Lee Myers and David Kirkpatrick have more on the divisions among coalition partners over the endgame for the mission and the exit strategy. Some have called for regime change but not within the military action, others have officially recognized the Libyan rebels as the representatives of the country, still others have called bombing of Gadhafi compounds fair game.

The best hope is some kind of negotiated settlement where Gadhafi exits and a transitional government takes over, and there have been some indications toward that end. But with the situation on the ground stalemated, I’m not at all optimistic of that possibility. I also agree with Matt Yglesias that bombing a country leads to an overthrow of a government by its generals is mostly a chimera.

I understand that some very respected people have lauded the UN-mandated no-fly zone as preventing a massacre in Benghazi. But I wonder if they can explain how this can end well and a strategy for getting there.

On a related note, read Nancy Youssef on the Libyan rebels, and the troubles among them.