Now that President Obama has decided to provide military assistance to Syrian rebels the next step is easy, says a military analyst who's been studying the Syria conflict.

U.S. intelligence has vetted the rebel forces to determine who should get the arms and it has a willing middleman in Turkey, on Syria's northern border, said Christopher Harmer, an analyst with the Institute for the Study or War.

A NATO member. Turkey has air bases and ports that U.S. forces have used in the past to move equipment and people to conflicts in Iraq and Afghanistan, he says.

Turkey's Incirlak Air Base, which is technically a NATO air base, is one likely hub for U.S. supplied weapons intended for the rebels, Harmer says.

"The US moves cargo through there all the time," Harmer said. Establishing a supply route to the rebels "is not that hard."

According to USA TODAY reporting in Turkey, the United States has already been sending communications equipment to rebels of the Free Syrian Army through Turkey. Rebels have said they have picked up shipments in Istanbul and driven them across the border into Syria along secure routes.

Turkey has sea ports for larger shipments. But most of the weapons rebel leaders have requested are light weapons, chief among them shoulder-fired missiles. The missiles are wanted to shoot down Syrian aircraft or disable Syrian tanks.

If the USA agrees to provide such weapons they can be delivered to Turkey by air, Harmer said. Arms could then travel by truck or rail to the Turkish border with Syria, and that's where U.S. control over the weapons will likely end, Harmer said.

The effort depends on Turkish cooperation. Turkish Prime Minister Recep Tayyip Erdogan has already allowed weapons from saufi Arabia and Qatar to transit through his country and supports the toppling of Syrian President Bashar Assad's regime.

The Syrian rebels control at least 20 miles of Syrian territory south of the Turkish border, "so there's no really no mechanical way for the Syrian government to stop them," Harmer said.

However, there is a risk that Syria will directly attack Turkey over the shipments. Syria has already fired missiles into Turkey territory along the border to target weapons shipments and rebel fighters who seek protection on the Turkey side of the border. Turkey has been hosting around one million Syrian refugees, and rebels have camps there as well.

The U.S. presence in Syria itself will likely be very small, limited to CIA or special forces operators, and focused on identifying rebel groups they can trust, Harmer said.

"We don't want to provide weapons to al-Qaeda affiliates" who are known to also be fighting the government in Syria, he said.

When the conflict started, the identity and motivations was not well understood. Harmer said two years have changed that situation completely. The Institute for the Study of War and other independent groups have completed extensive studies on the various rebel groups.

"We know from open sources, YouTube videos and interviews who are secular freedom lovers and who are the extremist religious types," Harmer said.