Assad and Hariri
"The diplomat I spoke with believes the reason the Asad family overruled the older generation of experienced Lebanon hands was that family members such as Bashar’s brother Maher and his cousin Rami Makhlouf had important business dealings in Lebanon which depended on Lahoud. 'They needed Lahoud to stay for their own interests,' he said. 'The family members were pushing for his retention. Perhaps they were trying to create their own Lebanon policy and side-line the ‘old guard,’' he added. 'Maybe Bashar went along because he is trying to create his own base of power?'"
I think it's been well over a year since I last posted on Syrian politics, but it is a mistake to see Bashar al-Assad as a man calling the shots the way Saddam Hussein was in Iraq. A couple of years ago Syria experts believed Assad served as a buffer between other political factions left over from the days when Hafez al-Assad actually did run the show. However, Bashar would clearly want to create a power base for himself as a means of survival should a faction ever decide to mount their own takeover. In this model, Lebanon policy could become chiefly about intra-Syrian politics rather than a collective Syrian foreign policy in the national interest.
But as Landis says, there's still nothing suggesting that the Syrian government was involved in the Hariri assassination. This brings us to the "rogue elements" some have suggested might have been responsible, as if Assad is becoming important in his own government, others would have an interest in countering him. This is politics at a very deep level, and I wouldn't count on getting a definite answer in the near future. Issandr El Amrani cites a report that Israel believes Hizbullah was responsible, which would explain where we find a suicide bomber. Hizbullah is, of course, linked to Syria. It is also supported by Iran, and has almost certainly cooperated with the IRGC in militant operations elsewhere in the region.