Libya has little of the geopolitical significance of Egypt - a pillar of the Arab world, key U.S. ally and regional powerhouse - but violent collapse in the vast, oil-rich, desert nation with its rival coastal cities raises the spectre of mass exodus and roiling instability.
Already thousands are fleeing the violence, streaming across borders into Egypt, Tunisia and Algeria.
Unlike the relatively orderly ousters of repressive dictators in neighbouring Tunisia and Egypt, Moammar Gadhafi's ruthless threat to crush all dissent or achieve martyrdom signals a cataclysmic final act.
After four decades ruling with vicious, unpredictable, brutality Colonel Gadhafi may have no where to go and his chances of a quiet retirement inside Libya seem remote.
Grim internal and external consequences are mounting.
Oil and gas exports have been cut - so far only as a precautionary measure - as foreign firms evacuate workers from remote desert runways.
Even if a civil war is averted the potential for strife remains huge.
If Col. Gadhafi manages to find a safe haven - and some suggest Zimbabwe's equally megalomaniac President Robert Mugabe might offer one - the nation he flees will be in chaos.
"Libya today faces a dark future in the short term. While Gadhafi's departure from the scene would be mourned by few, it would also create an enormous power vacuum," writes Robert Danin, a senior fellow at the Council on Foreign Relations. "Entirely unclear is what glue will hold together this largely decentralized country, in which nationalist identification is low, and tribal and clan affinity paramount. Unlike in neighbouring Egypt, the military lacks the cohesion or unity needed to hold together the country."
Egypt is a regional heavyweight with a storied past and a population of 80-million who shared deep and powerful attachment to their society's central role in Arab history. But Libya is largely a 20th century creation, a massive mostly empty, oil-rich country brutally ruled by Col. Gadhafi, whose stranger schemes included a pan-African union. The small, clan-based population of barely 6-million already had deep fault lines.
There are two widely separated coastal populations. One is concentrated in Tripoli, Col. Gadhafi's power base and the capital in the west. The other is in and around Benghazi, the eastern city that dominates oil and gas exports, and birthplace of the uprising.
"It's very difficult to predict what will happen with a regime that is so determined to remain in power at whatever cost," said Ash Jain, a visiting fellow at the Washington Institute who formerly was with the U.S. State Department. "It's very unlikely we will see a clean transition and there could be medium-term impacts felt beyond Libya."
While the cut-off of oil and gas exports might be short-lived and - given the spare global production capacity - easily replaced, the mass exodus of Libyan and others could create huge strains in the Maghreb and southern Europe.
Tens of thousands of Africans - many of them from Somalia, Ethiopia and Sudan - venture annually on the perilous cross-Mediterranean journey from Libya's long, unpatrolled coast, seeking asylum and work in Europe.
Col. Gadhafi has already extracted a $50-billion, 10-year payment from European nations to stanch the exodus, threatening to turn "white, Christian Europe .... black," unless he gets paid. Any relaxation of the draconian internal security regime run by the Libyan dictator would almost certainly increase illegal migrant flows, even without additional Libyan refugees.
"We're very concerned about the threat of civil war in Libya and the risk of migration towards the European Union, of epochal dimensions," Italy's Foreign Minister, Franco Frattini, said.
In the worst-case scenarios, outside military force - under the auspices of the United Nations - could be required to keep the oil flowing, stanch the migrant exodus and keep feuding clans apart.