American air strikes against the Syrian Government would not allow rebels to topple Bashar al-Assad because opposition fighters are too fragmented and disorganised, an intelligence analysis warns.
The uprising has broken down into countless battlefields fought over by a "vast array" of different rebel groups. Rebel fighters may be able to make local gains behind a barrage of missile strikes but are unlikely to overthrow Assad's Government.
The analysis from IHS Jane's, a defence consultancy, comes as American military planners have been told to widen a list of potential targets. President Barack Obama is considering using long-range bombers to hit Assad's forces harder and ensure they are unable to launch more chemical weapons attacks such as the one that killed up to 1400 people in an east Damascus suburb.
Charles Lister, author of the analysis, said: "While it is perfectly feasible that localised insurgent groupings could take advantage of strikes that target government air assets and key artillery positions, it is unlikely that this will lead to a nationwide surge in opposition victories and any perceivable imminent overthrow of the Government."
The US has five guided-missile destroyers and at least one submarine in the eastern Mediterranean, each loaded with cruise missiles. Planners are also considering bombing strikes from B52s or B2 stealth jets, which would be able to jam or evade Syria's air defences.
A hit list of targets being drawn up in Washington includes branches of the Government's secretive research centre where the regime is believed to develop chemical and biological weapons. There are laboratories in Damascus, Homs, Latika and Hama. Missiles will also hit the units thought to have fired chemical weapons. Stockpiles of the weapons, which include mustard gas and sarin, will be avoided because of the risk of leaks into civilian areas or of jihadist rebels stealing shells from shattered bunkers. Other targets include command centres of the Syrian army, Defence Ministry, and intelligence agencies in Damascus.
Obama may also add airfields to the list, said Jeremy Binnie, also of IHS Jane's. He said: "Some US politicians appear to want the strike to be aimed at more conclusively degrading the capabilities of the Syrian military, thereby swinging the balance of power in favour of the insurgents. In these circumstances, airbases would be a likely target."
Smashing runways at key airbases including Tiyas, Dumayr and Mezzeh would ground Syria's fast jets and stop planes bringing supplies from Iran. More effective could be destroying the Russian-made helicopter gunships used to attack rebels, or the transport helicopters supplying bases.
America is also likely to target mobile artillery, including Syria's fleet of around 50 Russian-built Scud missile launchers. Dozens were reported to have been seen on the move last week from Qalamoun, near Damascus, to unknown locations. The missiles they carry, mostly manufactured in Syria, have a maximum range of 320km. Rebels also want attacks on the government's elite forces.
Opposition groups warn Assad has moved equipment to civilian neighbourhoods and placed prisoners in military sites as human shields.
Michael Stephens, a research analyst at the Royal United Services Institute in Doha, said: "Assad has been moving a lot of things around recently. We have seen a lot of troop movements in central Damascus, particularly into civilian areas."
If the strikes are successful, they could bring Assad to the negotiating table, US officials believe. Samantha Power, US ambassador to the United Nations, said: "This operation combined with ongoing efforts to upgrade the military capabilities of the moderate opposition should reduce the regime's faith that they can kill their way to victory."
Dr Alan George, of St Antony's College, Oxford, said the Assad regime was not interested in a peace deal. He said: "Assuming they really are narrowly focused, the strikes will not alter the fundamental balance of power between the regime and its opponents."