Israel can try to smear Syria all they want; assassinations are not relevant. Syria and Iran now control Iraq. The US does not, and it lacks the "juice" to even whimper a compaint.
Syria and Iran don't _need_ Israeli permission to stabilize the region. They have the moral authority and the means to do it.
The Bush Administration can squawk and look stupid, or they can make like they came up with the idea in the first place. (A realistic assessment of one's capabilities is often useful.)