By key measures of the level of insurgent violence against US forces in Iraq -- numbers of dead, wounded and insurgent attacks -- the situation has grown worse since summer.
While those numbers don't tell the full story of the conflict in Iraq, they suggest insurgents are growing more proficient, even as the size of the US force increases and US commanders succeed in soliciting more help from ordinary Iraqis.
The US military suffered at least 348 deaths in Iraq over the final four months of the year, more than in any other similar period since the invasion in March last year.
The number of wounded surpassed 10,000, with more than a quarter injured in the last four months as direct combat, roadside bombs and suicide attacks escalated. When US President George W. Bush declared May 1 that major combat operations were over, the number of wounded stood at just 542.
The number of attacks on US and allied troops grew from an estimated 1,400 attacks in September to 1,600 in October and 1,950 in November. A year earlier, the attacks numbered 649 in September, 896 in October and 864 in November.
US commanders insist they are making progress, in part by taking the fight more directly to the insurgents. And they remain hopeful that more US-trained Iraqi security forces will join the fight soon.
Some observers are more doubtful.
"The prospects in Iraq are grim," Dan Goure, an analyst at the private Lexington Institute think tank in Washington, said Thursday. He assessed the conflict as a standoff, with no clear indication that either side will achieve victory in the coming year.
"Neither side can truly come to grips with the other so far and defeat them," Goure said.
US commanders constantly analyze the insurgents' tactics and make adjustments.
Yet although US forces have found tonnes of hidden weaponry and ammunition, the insurgents kill almost daily with makeshift bombs known as improvised explosive devices.
They plant the bombs along roads or stuff them into cars for suicide attacks.
Brigadier General Jeffrey Sorenson, a senior Army acquisition official, said Thursday it has taken the Army many months to counter the IED threat because war planners had not foreseen its scope.
"The violence of the IEDs, the sophistication of some of those IEDs, was never anticipated," Sorenson said. "I can certainly attest to that."
The toll is clear.
Pentagon statistics show that for all of 2004, at least 838 US troops died in Iraq. Of that total, more than 700 were killed in action, by far the highest number of American battlefield deaths since at least 1980, the first year the Pentagon compiled all-service casualty statistics.
It almost certainly is the highest killed-in-action total for any year since the Vietnam War.
US deaths averaged 62 per month through the first half of the year. But since June 28, when US officials restored Iraqi sovereignty and dissolved the US civilian occupation authority, that average has jumped to about 78.
Deaths among National Guard and Reserve troops are rising, reaching a single-month peak of 27 in November. At least 17 were killed in December.