Syrian rebels say "elements in the U.S. Congress" are blocking the delivery of arms that were promised to them by President Obama, part of a new U.S. effort to support an uprising against Syrian President Bashar al-Assad. Government forces are stepping up a broad offensive against rebel strongholds and making battlefield gains. Why is Washington holding back on sending weapons the rebels desperately need?

The Obama administration said a month ago that the deliveries would start within weeks. Karen DeYoung at The Washington Post says the push has stalled because members of the House and Senate intelligence committees, which would have to sign off on the plan, can't agree on how to handle sending light weapons and ammunition to the rebels — or whether to do it at all.

Some want a more significant U.S. commitment, saying that the administration's proposal is too little, too late. Others have voiced concerns that despite the administration's assurances, U.S. weapons will fall into the hands of Islamist extremists fighting alongside the rebels.

A significant number of lawmakers reject any increased U.S. involvement in Syria’s civil war and fear a slippery slope into another Middle East quagmire. [Washington Post]

The argument that the weapons could fall into the hands of Islamists, who could then use them against the U.S., appears to be the biggest stumbling block. Leaders of the Western-backed Syrian National Coalition have vowed to keep the arms out of the hands of extremist factions that are also battling Assad. The trouble is, says Matthew Feeney at Reason, "there is no way to guarantee that these groups would not benefit and further pursue their goal, the establishment of an Islamic state in Syria."

There is a hole in that logic, though. As Jamie Dettmer notes at Fox News, Syrian rebels are already benefiting from the increased flow of guns and money from oil-rich Persian Gulf states, and they are perfectly happy to send it to the same extremist, anti-Western Islamist factions the U.S. is trying to cut out.

The role of Saudi and Qatari governments and individuals in the funding and arming of Islamist fighters in Syria has been well known since the civil war began more than two years ago. But now, guns and money are flowing from private sources and Salafist-controlled NGOs based in Kuwait, and they are going to rebel factions aligned with al Qaeda. [Fox News]

Impatient rebels have another theory about what is behind the delay. Jason Ditz at Antiwar says they're accusing Israel of lobbying against supplying the opposition, on the grounds that the Islamist fighters could actually defeat Assad — and take over all of Syria. "Of course a lot of people are worried about that," Ditz says, "but the rebels also see not getting the arms as proof the U.S. wants to keep the war going."