I’ve been away from Iraq for 6 months and a lot has changed.

For the first time a brake has been put on the runaway violence. Increased US and Iraqi troop presence in Baghdad has lowered the daily culls by death squads. Now only a dozen or so sectarian assassinations are discovered a day. During my last visit the daily average was well over thirty. Some Iraqis I know feel a tiny little bit safer, let their daughters go back to University classes not so long ago they thought would be their death.

Sunni Tribal leaders I met last year who complained of Al Qaeda’s dominance in the Sunni west of Iraq al Anbar now tell me they can walk the streets of Ramadi with me. I know Tribal Sheikhs would never do that unless they could guarantee my safety 100%. They claim to have routed al Qaeda. It’s a sea change, they now hunt al Qaeda and work with Americans. 6 months ago, for many of them, it was the other way round.

But this is still the Iraq I know. These new brakes are burning hot. Metal on metal. The daily death toll is climbing again. New supposedly secure gated communities in Baghdad in some cases are little more than islands of safety in a sea of al Qaeda relocated from the west. Big car bombs still kill big numbers. US bombing campaigns against insurgents and militias still incense Iraqis convinced the US is the mother of all trouble makers. And worryingly the Sunni tribal Sheikhs of the west still expect their new anti al Qaeda force will one day be aligned against Shia forces when the big civil war begins.

This sense of impending sectarian Armageddon seemed all the more possible when I met Iraq’s top Sunni politician, Vice President Tariq al Hashimi. Just getting to him though was a trip my Baghdad memory lane. Just like before security to meet these tops officials is dizzyingly tight. I can’t give away security details, our lives depend on these secrets too. But we were searched no less than 7 times before we could set up.

We sat waiting for the Vice President in a marbled floored well appointed modern air-conditioned room. The chairs were gilt, the cushions embroidered with gold thread, a modern artist had tried to recapture Baghdad’s tranquil days in pictures of riverside scenes with mud houses long since pulled down by the last regime. Not far away a car bomber was preparing to set of his explosives in a crowded market. 33 people had no idea they were about to die, but in this room I could imagine the brakes were holding. Two suited office workers chased earnestly with a fly swatter and spray in hand trying to eradicate a rouge fly lest it bothered the Vice President. Maybe Iraq really had changed. Then Vice President Hashimi came in. The fly was dead, the car bomb had another hour until it would go off. He had his own bombshell.

Vice President Hashimi told me he is ready to pull out of the unity government convinced the country’s Shias, Kurds and even American’s care little for his Sunni input. He’s set a May 15th deadline for changes to the constitution and has already told President Bush he’s more than fed up.

-- From Nic Robertson, CNN Senior International Correspondent.