* Defeated, rebels would resort to guerrilla warfare 
* Insurgents would likely be based in eastern towns 
* Guerrillas would need secret arms cache network 
    
By William Maclean, Security Correspondent 

LONDON, March 11 (Reuters) - Far from ending Libya's conflict, a military victory by Muammar Gaddafi would see his enemies retreat to a few urban strongholds and relaunch their revolt as a grinding guerrilla war. 

A decisive win for the government in conventional military terms remains unlikely, in the view of many, but is no longer unimaginable: Enjoying supremacy in the air and in heavy armour, Gaddafi's forces appear to have regained the momentum in the OPEC member country's three-week old conflict.  

If Gaddafi's military advance retains the initiative, it could overtake cautious international efforts to halt him. A defeat for rebels even in their eastern heartlands is seen by some analysts as no longer beyond the bounds of the possible. 
Noting Gaddafi's forces were better equipped and disciplined than the opposition, National Intelligence Director James Clapper told a Senate hearing in Washington on Thursday that eventually "the regime will prevail."  

But analysts say a traditional military victory would not restore to Gaddafi complete control of the north African country of the kind he enjoyed in the 41 years of his rule to date.  

That is probably gone forever. 
Instead, eastern cities such as Benghazi that have been the historic heartland of opposition to Gaddafi's rule will likely resist complete government control. 
    
CRACKDOWN 

There, an urban guerrilla insurgency will be able to nest in the cities, drawing support from residents horrified by the government's violent crackdown on civilian protesters. It might also draw on the covert provision of foreign military expertise. 

Guerrilla chiefs would also be able to manipulate rifts in a ruling establishment now riven by numerous defections by army officers, tribal leaders and veteran former state officials. 

And Gaddafi and his entourage will be constrained by tightening international sanctions aimed at denying him access to funds, weapons and foreign travel. 

"If Gaddafi reasserts control it will be in the face of new tribal and regional divisions," said Yezid Sayigh, a professor in the War Studies Department at King's College, London. 

 "Large sections of the population will no longer be willing to provide the intelligence Gaddafi would need to confront an urban insurgency. There may be physical control of key state buildings but that's not like having real security control." 
  
Graham Cundy, a military specialist at Diligence, a Western security and intelligence consultancy, said there was no shortage of arms and ammunition in the east, the traditional bastion for disaffection to Gaddafi's rule.  
  
So urban centres in the region could provide havens for a core of committed fighters drawing on support from locals. 
"You've got everything that's required for a continued campaign of armed dissent against Gaddafi were he to reassert power," said Cundy, a former British military officer with long experience of guerrilla warfare in Afghanistan. 

Guerrilla warfare against an entrenched incumbent power requires safe areas where fighters can recuperate, rearm and plan, military experts say. Examples are mountains, captured territory, remote regions, a friendly neighbouring country or large cities which afford a degree of anonymity. 

Libya, more than 2-1/2 times the size of France, lacks mountains, and many of its remote regions might end up being controlled by groups of uncertain afiliation.  

As a result, said Shashank Joshi, associate fellow at Britain's Royal United Service Institute, cities in the east were the most likely places to emerge as bastions for the rump of a defeated rebel force. 
"What I think you are going to see is the northeast remaining a bastion of the opposition," he said. 
    
TOUGH RESISTANCE 

He pointed to the northwestern city of Zawiyah, taken by the army only after days of violent assault, as an example of the kind of tough resistance urban guerrilla forces could offer. But the rebels will have to up their game if they are to survive further assaults of similar ferocity, analysts say. 

Rebel commanders appear to lack an agreed strategy and a unified command, profound weaknesses for which their fighters' evident enthusiasm does not compensate, analysts say. 

Noman Benotman, who fought against Gaddafi as an Islamist guerrilla in the 1990s, said the rebels had to make haste and build a secret network of rural and urban bases in the east. 

In the event Gaddafi reasserted his grip on eastern towns, a web of arms caches, food, water and fuel would be essential to enable an insurgency to survive, said Benotman, who now works as a counter-radicalisation expert for British think tank Quilliam. 

"They need urgently to reorganise in the east, and they lack experience, which will be a problem. But if they can build those bases, they can wage a war without frontlines and create hell for Gaddafi's forces."