By Ed Cropley BANGKOK, Oct 15 (Reuters) - Cambodian and Thai forces exchanged fire at a disputed border area near the 900-year-old Preah Vihear temple on Wednesday. The following Q+A aims to clarify some of the issues behind the dispute: 1) If war broke out, would Thailand easily defeat Cambodia? Yes and no. The 300,000-strong Thai military has firepower that impoverished Cambodia can only dream of, including U.S.-made F-16 fighters and Blackhawk helicopters. Cambodia has a few MiG-21s that have never been known to get off the ground and a handful of ageing Soviet transport choppers. If it came to "all-out" war, there could be only one winner. The problem for Thailand is that it will never come to that. At worst, it could escalate into a series of jungle guerrilla battles similar to Thailand's 1987-88 border war with Laos in which the much larger Thai forces ended up with a bloody nose. Like the Lao, Cambodian troops are ill-equipped and poorly paid, but many are ex-Khmer Rouge soldiers who have only known peace in the last 10 years. They are tough and utterly ruthless. In addition, the entire border is seeded with millions of landmines, the legacy of decades of civil war, and any Thai advance would incur heavy casualties. 2) Apart from national pride, is there any reason to go to war over this scrubland? Not really, but national pride counts for a great deal in this part of the world, and temples including Preah Vihear -- or Khao Phra Viharn, as the Thais call it -- are inextricably entwined in the national psyches of both countries. The stunning Hindu ruins were awarded to Cambodia in 1962 by the International Court of Justice, a ruling that sparked uproar in Thailand, where the military government had asked every citizen to donate 1 baht to pay for its legal costs. A Cambodian mob torched the Thai embassy in 2003 after misreported comments from a Thai actress that the 800-year-old Angkor Wat temples deep inside Cambodia actually belonged to Thailand. Preah Vihear ranks second only to Angkor in Cambodian hearts. 3) Are domestic politics to blame for the rise in tension? Probably, in particular in Thailand where the government is under huge pressure from a five-month street campaign. The Thai military are also facing growing calls from the protesters to launch a coup, but are so far resisting. A border war with one of Thailand's traditional enemies would be likely to rally some support behind the government and army. The gains for Cambodia are less clear, especially after Prime Minister Hun Sen's huge victory in a July general election. However, the wily ex-Khmer Rouge commander knows he cannot let Thai aggression go unchallenged, and is probably keen to steal a march on his larger neighbour as it wallows in the worst domestic political upheaval in 16 years. 4) Are border disputes common in this bit of Southeast Asia? Yes. Long stretches of Thailand's borders with Myanmar, Laos and Cambodia have never been properly mapped, leaving considerable room for confusion and argument. In addition, huge flows of refugees and legal and illegal economic migrants from Cambodia and Myanmar since the 1970s have ensured they are porous to everything from narcotics to weapons. Cambodia is also very sensitive about its size, mindful of its 800-year slide from a Khmer empire that spanned the region to a small, troubled nation sandwiched between Thailand and Vietnam. Drummed into every school-child's head, its area -- 181,035 sq km -- is as etched into the collective memory as deep as "9-11" in the United States. 5) Surely the Association of South East Asian Nati will step in and solve the problem? No. Singapore has called for calm, but if Bangkok and Phnom Penh really decide to slug it out, there is nothing ASEAN's toothless diplomacy will be able to do about it. (Editing by David Fox)