By Angus McDowall and Amena Bakr
RIYADH/DOHA (Reuters) - Washington's last-minute decision to call off military strikes against Syria deals a blow to Saudi Arabia and Qatar, but the states that arm rebels battling President Bashar al-Assad will not soon give up on a war that has already cost them billions.
With Assad now looking unlikely to crumble soon and the West showing no desire to bomb him from power, the Gulf princes face few options beyond continuing to fund one side in a perpetual military stalemate that has already killed 100,000 people.
"If the U.S. doesn't launch an attack there's really no plan B drawn up yet by the GCC states," said an Arab diplomat, referring to the Gulf Cooperation Council (GCC) of six rich Arab countries. "What I'm telling you is simple: they have no plan."
The Sunni Muslim Arab monarchs see defeating Assad as fundamental in their confrontation with the Syrian leader's main regional patron, Shi'ite Iran.
Since 2011, Western leaders appeared to be on the same page, repeatedly demanding Assad be removed from power and insisting that no solution was possible unless he goes.
But the West's latest diplomatic efforts have been focused on dismantling Assad's chemical weapons stockpiles, not on removing him from power, leaving the Arab states alone.
Gulf watchers say Qatar, which began arming rebel units last year, and Saudi Arabia, which stepped in as the main supplier this year, will keep the weapons coming.
"There is no way that Qatar will let go of their support for Syria now. This is a very personal issue for Qatar as they feel a close connection with Syria," said a source close to the government in Doha.
Abdulaziz al-Sager, head of the Gulf Research Centre in Jeddah, said the same was true of the Saudis.
"I would not be surprised to see much more open Saudi support for the rebels," he said, adding that the situation argued for closer coordination between Saudi Arabia, Qatar and Turkey, another ally of the rebels.
The problem is: no matter how much they spend, it no longer seems possible for the Gulf rulers to purchase victory.
There is already no shortage of light weapons, such as AK-47 rifles and rocket propelled grenades, which have poured into Syria for months. The Gulf countries have also been sending some more advanced weapons, like anti-tank and anti-aircraft missiles, but are reluctant to send too many for fear of them falling into the hands of rebel units allied to al Qaeda.
A source close to Gulf governments said this meant they did not have plans to supply "game-changing weapons".
Nor is it clear that weapons alone would be enough to turn the tide in a war that has gone Assad's way since the start of this year, when he won the backing of Lebanon's Hezbollah militants to reverse rebel gains in the center of the country.
Some voices have begun arguing for the Gulf states to take direct military action on their own without Western support, something they have never really done despite arming themselves for decades with some of the world's biggest defense budgets.
"The United States was always there for us for the last 50 or 60 years. But after this incident it was not. Saudi strategists have to think about the new realities," said Jamal Khashoggi, who runs a television news channel owned by a Saudi prince and co-wrote an op-ed piece in the New York Times calling for Arab states to act without waiting for the West.
But most observers see any direct action as unlikely.
"They will not launch a strike themselves of course: they don't have the forces or the numbers. And if they just keep providing the rebels with weapons that will not change the situation," said the Arab diplomat.
Diplomats say the Gulf states have been counting on Western intervention of some kind to help the rebels, at least since the battle of Qusair in March, when Hezbollah fighters helped Assad's forces to a big victory and tipped the war's momentum in the Syrian leader's favor.
"They always wanted Western support. Partly from Britain and France. More importantly from the U.S. Until the start of this year they thought they could do it (bring down Assad) themselves. Now they think they can't," a diplomat in the Gulf said soon after that battle.
The source close to Gulf governments said one big reason the monarchs had hoped for Western air strikes was that this would help level the military playing field without flooding Syria with the sort of heavy weaponry that would be hard to deal with after the war.
Syrian rebels are still counting on Gulf support, even as international diplomacy is expected to shift towards promoting a peace conference in Switzerland to follow on an inconclusive meeting in Geneva last year.
"In front of everyone, the Gulf states will join the international community in going through with Geneva 2, but under the table they will still continue to provide all kinds of support to the opposition in Syria," said Nizar al-Haraki, the Syrian opposition envoy in Doha.
Khashoggi, the Saudi news station director, said the lack of help from the West was proof that the Gulf states need to develop the capability to act militarily on their own.
"The message from the West is clear: we are not interested in your problems, your sectarian divisions, your infighting, your Arab Spring struggles," he said.
But few think the issue is going to wean the Saudis and other Gulf states from their dependence on the United States to provide security, which limits their ability to act alone.
"You hear a lot of talk about not being able to rely on the U.S. But when it comes down to it, they continue to insist that it should be the U.S. that takes action," said Robert Jordan, Washington's ambassador to Riyadh from 2001-03.
"We still have a lot more in common than separates us. There's still a very strong convergence of national interests in resolving this crisis and we will continue to work together even though we don't see it exactly the same way," said Jordan.
(Reporting by Angus McDowall and Amena Bakr; Writing by Angus McDowall and Peter Graff; Editing by Giles Elgood)