US-led military strikes on Syria would boost all of the country's opposition forces, including jihadists, but would not be enough to precipitate the fall of Bashar al-Assad's regime, analysts say.
US President Barack Obama is seeking congressional authorisation for limited military strikes on Syria in response to an alleged chemical weapons attack in the suburbs of Damascus on August 21.
The strikes are being seen by some, including the US-backed rebel Free Syrian Army, as an opportunity to decisively shift events in favour of the opposition.
Indeed some US backers of military action say boosting rebels on the battlefield should be a key goal of any US-led strikes.
"Without the provision on reversing the momentum on the battlefield, then conditions are not created for the departure of (Syrian president) Bashar al-Assad," Republican Senator John McCain said this week.
"There is no policy without that, and there is no strategy without that."
But the limited strikes Washington is considering, as well as the nature of the Syrian conflict, will make creating a nationwide momentum for the rebels difficult, experts said.
"Syria consists of countless localised conflict theatres, and the dynamics within each one are unique," said Charles Lister, an analyst at IHS Jane's Terrorism and Insurgency Centre.
"Strikes are highly likely to impact localised battlefields... (but) shifts on a more nationwide level are less likely, although opposition progress in some areas surrounding Damascus and Aleppo is possible."
Aron Lund, an expert on the Syrian uprising and Islamist movements, was similarly sceptical that strikes would produce a nationwide shift, though he said local reversals were possible.
"Rebels do not coordinate well across the country, but if attacks are focused on a particular area, this could result in a local breakthrough."
The diversity of the forces fighting Assad's regime will also make it difficult for Washington to ensure benefits only accrue to battalions it backs.
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"A recent communique about skirmishing between rebels in the Palestinian refugee camp Yarmuk and a neighbouring area... counted 11 different groups involved in that single battle in that single area alone," Lund noted.
In some areas, there are more obvious beneficiaries, including around Damascus, where the FSA-affiliated Liwa al-Islam group is dominant.
"Several dozen FSA-branded groups operate (there) in loose alliances, but the powerful Liwa al-Islam may have the potential to benefit most," Lister said.
In other areas, however, the beneficiaries are less clear, and jihadist groups could stand to gain as much as US-backed fighters.
In addition to the Free Syrian Army -- a grouping of battalions answerable to a military command under General Salim Idriss -- a number of Al-Qaeda affiliates are fighting.
They include the Al-Nusra Front, which has pledged allegiance to Al-Qaeda leader Ayman al-Zawahiri, and the Islamic State of Iraq and the Levant (ISIS), the Iraqi branch of Al-Qaeda which has recently expanded into Syria.
"Western military action will have the potential to benefit any armed opposition group in Syria," Lister pointed out.
Speculation remains about what targets the United States might choose, with at least some strikes likely to focus on facilities linked to the chemical weapons that prompted the attack.
If the administration wants to help rebel forces, "air bases would be a likely target," said Jeremy Binnie, a senior security analyst at IHS Jane's who has examined potential targets.
"However, this would not make too much difference to the conflict, as the Syrian military is more reliant on surface-to-surface weapons," he wrote in a recent analysis.
Other targets could include resupply helicopters or military headquarters and communications infrastructure, which would hit the army's ability to coordinate operations, he added.
FSA spokesman Louay Muqdad said the group was not coordinating with Washington on the strikes, but was ready to take advantage of any openings they might create.
He said jihadists would not be the main beneficiaries, while insisting the FSA had been promised advanced warnings from the United States of what targets would be struck.
"For the Americans, these strikes might be cosmetic, but for us, we will exploit them as a gateway for the collapse of Bashar al-Assad's regime."