Libya crisis: Dangers ahead for coalition
There is a familiar and worrying rhythm to humanitarian interventions.
First, intervening powers insist to sceptical electorates that the campaign will be wrapped up in days. Second, they pound the low-hanging fruit - obsolete air defences and tanks on desert roads - with expensive missiles. The regime slinks into the shadows, and safe havens are carved out under allied air cover.
What follows is usually less simple - in 1990s Iraq, a dozen years of constant air patrols costing $1.5bn (£915m) annually; in Afghanistan, a decade of ongoing loyalist insurgency; in Kosovo, a protracted air war culminating in the further vivisection of the Balkans.
Much of this experience suggests that it is crucial to understand the strategies employed by the targeted state.
In degrading Muammar Gaddafi's heavy armour and air power, the coalition can rightly claim to have stemmed both the assault on urban areas and the prospect of retribution against civilians that prompted the historic UN resolution.
But sustained air strikes run into diminishing returns, and Gaddafi's strengths are not rooted in such easily crippled conventional forces.
In using human shields to protect key installations, for instance, Gaddafi emulates a favoured tactic of crumbling despots the world over.
But their deeper purpose is strategic. In ratcheting up the risk of civilian casualties, Gaddafi is pitting the more committed members of the coalition against its warier participants.
Britain and France, convinced that military action must eventually point towards regime change, want to hit a wide range of targets. The United States insists that regime change, though desirable, is not the purpose of this attack.
This is a neat reversal of alliance dynamics during Nato's intervention in Serbia and Kosovo in 1999.
Washington grew increasingly frustrated by having to approve target lists with Nato's lumbering bureaucracy, and eventually began a virtually independent bombing campaign.
Today, it is French concern over American circumspection that explains their hostility to running the war through Nato channels.
But the dramatic imagery of missile attacks has already frayed Arab support, the sine qua non of America's involvement. All this means that a single stray bomb landing on a hospital or school will fracture the alliance along these fault-lines.
Gaddafi will seek to hasten that process. He will do so not just by placing military assets next to sensitive sites but also through using plain-clothes soldiers to attack civilians deep inside urban areas, out of the reach of ground attack aircraft.
In 1999, Slobodan Milosevic accelerated his ethnic cleansing in Kosovo after intervention began. That kicked off a bitter coalition debate over the need for ground forces.
Similar atrocities in Gaddafi-controlled areas would sow discord between those advocating for an expansion of war aims, and those - like the influential US defence secretary Robert Gates - fighting to tightly constrain the war.
It is worth recalling that Europe's worst post-war massacre - at Srebrenica in Bosnia-Herzegovina - occurred under a no-fly zone.
Gaddafi's forces continue to punish civilians in Misurata, and remain in striking distance of urban areas in the east. In short, Gaddafi's greatest strength is his ability to force an unwelcome choice between escalation and leaving civilians in harm's way.
The rebels, in turn, are not yet a viable military force.
Even if they can retake Brega and Ras Lanuf, it is unlikely that the rebels would sweep Sirt - let alone Tripoli and its surroundings.
Gaddafi's security forces - bound by ties of clan, family and history rather than professional obligation - show no sign of peeling away.
The asymmetry in forces has been lessened by the no-fly zone and degradation of the government's heavy armour, but rebels control minimal artillery and tanks of their own. Arms supplied by Egypt are likely to be lighter weaponry.
In any case, their severest problem was one of organisation.
In both Kosovo and Afghanistan that problem was eased by US-led special forces who fashioned rebels into proxy armies under the cover of American air strikes.
In Libya, the US is unsure of the opposition's intention and has no appetite for serving as the rebels' air force and high command. Rebel fighters are not civilians and do not therefore enjoy protection under the terms of the UN resolution.
One of their options is to engage in combat in built-up areas and tempt loyalists to use artillery.
This might compel patrolling aircraft to supply "close air support". Additionally, subversion of oil installations could hit the government's purse strings, but this probably cannot be done on a meaningful scale.
What this suggests is that neither the rebels nor the "maximalists" in the coalition - those who see Gaddafi's departure as this intervention's endgame - have no good strategy to produce that outcome.
The best attainable conclusion may involve the irreversible degradation of the regime's firepower and the injection of Arab League and African Union peacekeepers.
Unless detailed planning for a managed stalemate begins now, Gaddafi may succeed in his effort to chip away at UN forces until the Franco-British rump collapses under the weight of its own contradictions.
Shashank Joshi is an Associate Fellow at the Royal United Services Institute (RUSI), a defence think-tank in London, and a doctoral student of international relations at Harvard University.