U.S. President Barack Obama, seeking to win re-election in November amid a weak economy, doesn't want to become entangled in a conflict in Syria.
But, some analysts say, letting the Saudis and their neighbors funnel arms to the disparate forces arrayed against embattled Syrian President Bashar al-Assad gives the administration a fair bit of wiggle room.
The Americans say they fear that arming the Syrian opposition, particularly the Free Syrian Army slowly taking shape, will accelerate a long-dreaded civil war that would then be harder to stop.
At the recent Friends of Syria conference in Istanbul, the Americans and their allies warned that unless Assad called off the regime's attacks on Syria's people and implemented a U.N.-backed peace plan, rebel forces will be provided with weapons from outside, sharply ratcheting up the intensity of the insurrection.
"That in effect gives Washington's blessing to a Saudi Arabian bid to arm the opposition," the Financial Times observed.
At the very least, it marked a shift in the U.S. administration's position of seeking to avoid a sectarian civil war in Syria, primarily between the Sunni Muslim majority and the Alawite minority regime, that could spill over to Lebanon, Iraq and Jordan.
Memories of Afghanistan and Iraq are never far away.
Britain and Turkey have indicated they wouldn't stand in the way of the Saudis and the gulf states.
Western officials say they haven't detected large-scale weapons transfers to the FSA, which is seeking to forge a cohesive alliance among the fragmented Syrian opposition groups.
But they said the Saudis, who have long been firmly opposed to the Syrian regime founded by Assad's father in 1970, are turning a blind eye to arms purchases for the FSA by opposition Syrian businessmen in the Persian Gulf.
Syrian opposition figures have been reportedly meeting Saudi intelligence chiefs in Turkey and Europe to determine what arms the FSA needs.
Anti-tank missiles to counter the regime's crippling armor reportedly have top priority.
"The decision to arm the rebels has been taken in principle but it has not yet been implemented," said Mustafa Alani of the Gulf Institute of Strategic Studies, a Saudi-funded think tank in Dubai.
Russia and China, Assad's main diplomatic friends after his Iranian allies, have stymied U.N. and Arab League efforts led by former U.N. Secretary-General Kofi Annan and backed by the West. The breakaway move by the gulf powers may have short-circuited those.
But, at its core, the Saudis' strategy has more to do with the Sunni-Shiite split in Islam, Syria's Alawites being a Shiite offshoot, and countering Iran than anything else. And in the long run, that religious fissure is probably more deep-rooted and enduring than any other factor concerning Syria.
There are wider considerations for the Americans. They've found that on the geostrategic level the conflict tearing apart a longtime opponent who has frequently stymied U.S. policy in the Middle East has other benefits.
The Saudis and their partners are increasingly at odds with Moscow and Beijing, who have blocked international initiatives Damascus didn't like.
That suits the Americans just fine. They've been alarmed at the diplomatic gains Russia and China, eyes on the gulf's oil, have been making in the Middle East of late, mostly at the United States' expense.
"Taking advantage of the profound sense of insecurity and alienation sweeping the Saudi regime, the United States is about to realize the dream project of shepherding the GCC states into its global missile defense architecture," observed veteran regional analyst M. K. Bhadrakumar.
The gulf states, long-riven by historical dynastic rivalries, had balked at working together on missile defense until the Iranian threat began to loom large in recent years.
Now, Bhadrakumar noted, "geopolitically the arc of the United States' global missile defense system extending from Central Europe through Turkey is … poised to take a leap across the Middle East to graze the waters of the Indian Ocean.
"In sum, Washington ties in the oil-rich Persian Gulf and can always revisit the crisis in Syria in due course."