It's worth remembering that, unlike the Iraqi government that we actually toppled, the Assad Regime that became embattled in a domestic conflict against its own people actually was a widespread supporter of terrorist organizations, including Al Qaeda in Iraq. In fact, it was probably one of the largest state sponsors of terrorism in the Middle East if you don't count Saudi religious missionary spending. I've been a bit surprised at how nostalgic some people have seem to become for the good old days of enemy dictatorship past.
Source on Assad supporting Al Qaeda in Iraq? It wouldn't make sense for him to do so.
Reality check: The Saudis\Wahhabis (US allies) have been the highest source of terror\suicide bombings in Iraq since the US invasion. Lets not try to spin too much here.
Syria has long been a major state sponsor of terrorism in the Middle East. Iran Is a pretty large supporter of external militant and terrorist organizations as well in both central Asia, the Middle East, and North Africa. The other large one was Libya under Gaddafi.
The role that many Gulf States like Qatar, the U.A.E. etc play tends to be different than Iran, and Syria. Saudi Arabia was a mix of the two strategies. A lot of money for terrorism is funneled through non-state actors in the Gulf. So the U.A.E. was a big staging point for funds for Al Qaeda Central, and a lot of Gulf Charities can redirect funds to terrorism organizations as well as individual financiers.
Syria's role has been reported for years by the Combating Terrorism Center, IHS Janes, The Institute for the Study of War, the Jamestown Foundation's Terrorism Monitor, SITE intelligence, and the Long War Journal. It isn't really a secret or unknown aspect of the Assad regime's past state sponsoring of terrorism. We've also conducted several raids against AQI stationed in Syria long before the current civil war.
Even now though Assad still funnels money to the ISIS in exchange for oil (as reported by the Terrorism Monitor of the Jamestown Foundation) even as they fight each other.
I'd be happy to find more detailed sources for you when I have more time later, but here is one small article from the Long War Journal detailing one incident:
http://www.longwarjournal.org/archiv...an_officia.php