Commentators have been comparing the current Libyan campaign with Bush 2003 in Iraq, hoping to launch the following viral conceit: liberals/Democrats are judging Obama by different standards because the multilateral justifications for use force in the Libya air campaign are equivalent to the arguments which propelled the Bush administration's March 2003 unilateral decision to invade Iraq invasion. Putting aside for a second the fact that a lot of liberals and Democrats have indeed expressed major reservations to outright resistance to the current U.S. use of force, I don’t think Bush/Iraq and Obama/Libya equation stands up to serious analysis. The U.S. is not invading Libya, but engaged in a limited air campaign akin to Iraq’s decades long no-fly zone (a more apt comparison) and Clinton’s Serbia-Kosovo campaign; Hussein was not actively engaged in a large-scale attempt to liquidate one of his own cities when a vast U.S. invasion force removed him and his entire Ba’athist political superstructure from power. The Bush administration ran through a series of justifications for its Iraq adventure, which eventually included a humanitarian appeal that was for a number of reasons deeply cynical.
I think it is likewise cynical to allege that Obama began this current campaign to shore up his domestic image and project power. He had to be dragged into this decision by the French and the British (who remain eager to go further than Obama), and it’s pretty clear he hopes to be out of Libya at the first opportunity.
The U.S. had two opportunities, probably more, to intervene in Iraq based on humanitarian grounds. Have we forgotten already? In 1988, Iraq forces used chemical agents to attack the Kurdish city of Halabja, killing thousands of men, women and children, almost all noncombatans. That assault could have (should have) provoked a “responsibility to protect” style intervention such as we are witnessing now in Libya. Instead the Reagan Administration, including a cast of characters who would later decide that what happened at Halabja indeed required Hussein’s removal (only in 2003 this time) tried to shift blame for the murderous gas attack to Iran. See, we were realpolitik pals with Hussein in those days.
At the end of the Gulf War, the Shi’ites in Iraq’s south and Kurds in the north took to heart President Bush encouragement to overthrow Saddam Hussein’s regime and launched an ill-fated resistance a day after the U.S. signed a cease fire with Hussein’s military in March 1991. After it became clear that the entire southern Shi’a population would be punished for this outrage, thousands killed, and millions of Kurds put to flight, the U.S. had another opportunity—and material in the area to support it—to launch an intervention based on humanitarian grounds. The Bush I administration elected not to support the uprisings, following the logic that too much chaos would erupt in the wrong kind of removal of Saddam Hussein. Although under the terms of the Gulf War ceasefire, the Iraqi military was not allowed to use fixed wing aircraft, U.S. forces did not intervene when Iraqi helicopters were used to devastating effect against the Shi’a in the south and Kurds in the north.
None of this is to say that what the president is doing now in Libya is good or wise (It may be good without being wise); it’s just to say, this is not the same situation and no amount of domestic political point-scoring can make it so. I must confess that the distinction to me the shooting of demonstrators in Yemen and Syria and intervening when civilians are targets in Libya or elsewhere (what would the U.S. do in the event, for instance of a Tiananmen square replay under RtP?) is a case of scale not kind. Scale does matter, however, less the RtP is invoked for hundreds of outrages around the world.
The responsibility to protect  as an international doctrine is still pretty young, emerging out of experiences like Halabja, Rwanda and Kosovo. It will likely take a long time before it hardens into an accepted international structure for triggering multilateral intervention to forestall another country's internal use of force. There may be missteps as this doctrine develops. This may indeed be one of them. As I type these words, the NATO (i.e., U.S.)-led coalition has just committed itself to the removal of Qaddafi under the belief that his departure is the only way to assure the safety of civilians in Libya’s east. We are heading into a dangerous expansion of the aims of the campaign and the resulting responsibility to the civilians who will left behind when the firing is over, with Qaddafi out or holding on. If the coalition is not successful or if the people the coalition is protecting exact their own unrestrained revenge on Qaddafi loyalists in the west of Libya, it could set back the notion of the international responsibility to protect immeasurably just as this important doctrine was beginning to find general acceptance.