It(intel) had to be a smoking gun..
There's likely going to be a lot of twists and turns in this Syria thing before it is done, but the really fascinating thing is that so many pressure points came up almost simultaneously. Watching HOW they play it out may give a lot of insight to unspoken undercurrents.
Syria's options are fairly limited. Militarily, Syria simply can't withstand an American or Israeli military offensive in Lebanon.
Which leaves Syria with non-military options. One such option is to finger Iran. Should Syria turn on Iran, blame the mad mullahs for the bombings in Lebanon, Iraq, and Israel over the past three weeks, and then turn on those terrorist groups that operate in Syria and Lebanon (e.g. Islamic Jihad, Hezbollah), then Syria will escape full-scale military defeat.
Another option is to withdraw from Lebanon immediately and simply lay low until peacenik regimes take over eventually in both the U.S. and Israel.
For our part, we have to insure that Syria isn't behaving this way as a deliberate distraction from Iran's nuclear program. If Syria is willing to shed blood to gain Iran a few months worth of time for their nuke program, then this whole matter takes on a different parameter.
Other than that angle, Syria is about to be out of Lebanon one way or another...and Hezbollah is about to get itself disarmed per UN resolution 1559.
What Israel had and maybe we had, went beyond a smoking gun. It left a high explosive trail right back to A$$ad and some of his buddies.