The top US military commander in Iraq is soon to report to President George W Bush on progress in containing violence in Iraq. He will use a series of benchmarks to measure success or the lack of it. Richard Galpin has returned to Baghdad after two years to see what change there has been.
Increased security makes life in Baghdad extremely restricted
As my plane made the steep, tactical descent to Baghdad airport, I was thinking about those much debated American benchmarks and realised that, almost subconsciously, I had developed my own.
Mine are, of course, deeply unscientific and highly personal - if not slightly eccentric - but they help.
The first is the width of our street.
When I first came to Baghdad just after Americans troops had marched in four years ago, we lived and worked in a normal street.
We walked around freely - even at night - taking just basic security precautions.
But this did not last long.
The American military floundered, not knowing what to do after taking Baghdad because it did not have a serious plan for the day after declaring victory.
That let members of the former regime seize the initiative, launching a well planned campaign of guerrilla warfare which also attracted Islamic extremists.
So over the next two years, our lives in Baghdad became ever more restricted.
Our street was sealed off and guarded, and it became increasingly narrow as each building had huge concrete blast-barriers placed in front of it.
By the time I completed my last tour of duty in the autumn of 2005, it seemed that every possible step had been taken to protect us from attack. But not so.
On my return here two weeks ago, I discovered our street was even narrower because yet more blast-barriers had been brought in.
It is now also much shorter, cut in half by a huge metal gate. And everywhere there are security cameras.
Living here is deeply claustrophobic.
What had previously felt like a reasonably relaxed prison, has now been transformed into a maximum security jail whose inmates - in other words us - are rarely let out.
Even government ministries have now been added to the long list of forbidden territory.
Where once we could go to spend time speaking with top members of the Iraqi government, we now fear to tread because of the threat of being kidnapped.
And that is because at the end of May, a British consultant and his four British bodyguards were seized by gunmen from inside the finance ministry in Baghdad.
Their fate is still unknown.
The incident says so much about the current state of the Iraqi security forces.
The kidnappers were all wearing police uniforms and drove up in police vehicles - clear evidence of the involvement of militia groups within the police force or, at the very least, collusion between the two.
Despair and grief
My second benchmark is the face of an Iraqi friend here.
Over the past four years, I have seen his face evolve into a picture of dejection. But now there seems to be something even worse: despair.
He is trying to persuade members of his own family to move abroad for safety even if it means being apart for years. Such is the fear of both random and sectarian violence in this city.
But this is minor league compared to what our colleagues at an international news agency have been through.
A few days ago, I attended a wake for two of their Iraqi staff - a photographer and a driver - who were killed in Baghdad in July.
An American Apache helicopter opened fire on them. The US military says it was engaged in a fire-fight with insurgents at the time.
In total, the agency has now lost seven staff since the invasion.
The photographer was just 22 years old and an exhibition of some of his most powerful images had been put on display for us to see.
Most of his short professional life had been spent chronicling just one thing: the violence tearing apart his own country.
And that brings me to my third benchmark, the board in our office.
Every day it is used to compile a list of the shootings, bombings and other violent incidents we hear about around the country. Last week we decided the board was too small. We needed something bigger.
Recipe for war
My fourth and final benchmark is a more direct look at how the American troops now operate on the ground.
It derives from a brief trip we made with General Raymond Odierno, the second most senior American military commander in Iraq.
A great bull of a man with a shaved head, he had some very specific people he wanted us to meet.
They are known as the volunteer security forces or civilian guards.
They have sprung up in the wake of the surge of American troops across central Iraq this year, which has had some success in quelling the violence in some of the most troubled regions.
Thousands of volunteers - all Sunni Arabs - have been stepping forward and offering to protect their own neighbourhoods. Some are former insurgents who have switched sides.
Others are young unemployed men who have had enough of the violence.
It is a remarkable turn-around that so many now want to co-operate with the Americans, the very people they had previously been trying to kill.
The Americans have been eager to sign them up and give them contracts - 20,000 apparently so far.
In the Sunni district of Baghdad we went to, the volunteers are filling a void because there are no regular police there as the police are mostly Shia.
While the Americans are enthusiastic about this growing force, the majority Shia population is becoming increasingly alarmed.
They fear that a Sunni militia of dubious loyalty to the government is being created across the Sunni heartlands.
And if the Americans hand responsibility to them and then pull back, it could be they have created the perfect recipe for all-out civil war.
From Our Own Correspondent was broadcast on Saturday, 1 September, 2007 at 1130 BST on BBC Radio 4. Please check the programme schedules for World Service transmission times.