There has been talk about the Obama administration helping the Syrian rebels with weapons. Personally, I think its all a farce. The Gulf states have been arming the rebels with everything money could buy so what would the Obama administration give the rebels that money can't buy?
There are some sort of weapons that the US could send that are hard to get but the question is, what would these weapons do to an ally like Israel if they are turned around and aimed at Israeli troops from the Golan heights?
Well, in my opinion, if the rebels take over the Syrian army stockpiles, there is a lot of danger to the Israeli citizens from what the rebels could use including in the extreme case; Chemical Weapons. However, in my humble opinion, I don't see the rebels taking over anything in the short terms and I do see this war continuing on for years.
So, lets review what the US could give the rebels that could be harmful to Israel:
1. Anti Tank Missiles - These missiles could be turned around and target Israeli patrols on the Syrian border. Dangerous but not uncontrollable. The Israelis could identify teams close to their border and destroy them potentially before they are able to set up positions to launch these missiles. An example of that you can see on the Israeli border with Gaza.
2. Anti Aircraft shoulder missiles (Stingers) - These missiles proved to be very effective against the Russian helicopters in Afghanistan when they were given to people like Osama Bin Laden (yes, the US gave weapons to people like Osama to fight in Afghanistan and look what happened there)
3. Heavy weaponry like tanks - Not possible
4. Mortars - Yes but not that accurate or dangerous. Israeli Tamouz missile could hunt these mortar teams and destroy them
5. Night vision equipment - Yes, this in my mind is the most dangerous weapon the US could give the rebels.
So, the control of what weapons are sent is important, the danger is there but could be defended against but the question remains, would the US really give out these weapons and would they try to account for what happens to them? As history suggest, the answer to both of those question is probably not.