I see, now we're going to go off and hide in semantics. Okay.
It is readily apparent that Syria and Iran (among others) are putting significant pressure on the Iraq situation. This is more of a regional fight for dominance than I first suspected. I don't understand the insistence that Iraq -- from WMD to "the insurgency" -- be spoken of as if it were in a vacuum.
This will go alot faster if you'd just agree with me.
Ok, time for simplification. This is how I see it - you just tell me the bits you disagree with. That is to say: if you disagree, tell me where and why - it's called debate. It's fun. Ok:
Syria is Ba'athist secular - predominantly Marxist in the old guard but Asad himself being Alawite Sunni in terms of lineage.
Iran is Shi'i.
Let's assume we can agree they won't be co-operating or supporting the same groups, if support there be (I hope we can agree on that or there's REALLY no point).
Any support from Syria will not be at governmental level but will only be from sympathisers with the insurgents. These are few, mainly because they are imprisoned, tortured and killed when found but some exist, I grant you.
So, these are at risk of detection from the US, Iraqis and Syria. If they are interfering it will be to promote Sunni Jihadi groups. But there are few of these.
Obl and Zarqawi cells are active (let's say for arguments sake) but these are Wahabi (ie Saudi) and will not be supported by the Syrian groups if they exist. In fact I can think of only one Syrian group - the Muslim Brotherhood, and that is all but extinct there.
The question of Syria as a 'safe haven' for non-Syrian insurgent cells is a different one and imo highly unlikely - for the simple reason that Asad knows he is next on Bush's hitlist and will not give the US the slightest pretext to invade. He will find these groups in a second and destroy them. Unless you think he is stupid in which case the debate stops there.
Iran: Sistani already has the Shi'i vote wrapped up. He also has the US on side, for now. There's nowhere else to go. Why would Iran interfere ? He will win hands down - even if the Sunnis vote. Which they won't.
So, why would Iran risk interfering in a vote that a Shi'i cleric is a dead cert for ? And how would they 'interfere' ?
Arming cells ? Funding insurgents ? Problems here - Sistani is working with the US to root out the insurgents - it is solely down to him that the Shi'i have not risen against the US. They may want to but he says no. The only person who ever disobeyed that fatwa was as-Sadr and Sistani sorted him out when the US couldn't.
Sistani has too much power for anyone to be successful at a rebellion if he doesn't want it. Iran know that. He has too much power for them even, he it THE major Shi'i figure and he disagrees in part with Iranian clerics.
So, what you say is not true. It could easily become true - I believe it will when the elections fail and if subsequently Sistani takes the reins off his followers. But it isn't true now.