If US military forces wanted to, they could lob artillery shells and perhaps even mortar rounds into downtown Baghdad. They're that close now.
But they won't. They'll continue probing Iraqi defenses with aggressive patrols, use more "coercive targeting" by strike aircraft, and increase Special Operations efforts against regime leaders and symbolically important sites. Then they'll try to break up the city into enclaves to limit enemy movement.
Above all, they will exhibit "tactical patience."
This, according to military officers and other experts, is how the endgame for control of Baghdad is likely to unfold. It will be forceful and relentless, but it will be carried out with caution as well.
"We are not expecting to drive into Baghdad suddenly and seize it in a coup de main or anything like that," says Army Maj. Gen. Stanley McChrystal, a senior staff officer for the Joint Chiefs of Staff. The Iraqis "may just suddenly be effective on the ground."
How effective Iraqi forces still are - particularly how hard they will fight within Baghdad - is the most important and the most dangerous unknown. While two Republican Guard divisions south of Baghdad have taken a pounding, four more divisions have been moved from their northern positions toward the city. The Special Republican Guard - the most loyal, the best-equipped, and the best-trained forces - are specifically tasked with protecting Baghdad. And thousands of nationalistic Iraqi civilians, who may not like Saddam Hussein, but who would fight any invader, have been given AK-47s and ammunition.
Some officers worry about the apparent folding of many Iraqi forces, concerned that this could be a tactic as old as Genghis Khan - who withdrew his forces at first contact to lure his enemies deep inside his own lines.
"I'm a little suspicious of the sudden melting away of the Saddam Fedayeen in south and central Iraq and at the same time the Republican Guard divisions," says retired Army Col. Daniel Smith. "Where are the bodies and prisoners that would indicate a broken unit? Someone should take a head count of bodies and burned out tanks on the battlefields and the number of prisoners and then come up with a estimate of enemy strength that has not been destroyed."
Many Iraqi soldiers no doubt have been killed or wounded, some have surrendered or been taken prisoner, and some may have shed their uniforms and deserted. But others may have fallen back to regroup for the urban battle.
"We know that there are still a number of forces on the battlefield that have not been joined significantly in battle, and what choices they make we don't know," says Army Brig. Gen. Vincent Brooks of Central Command headquarters in Qatar.
How the war has gone so far may be instructive.
"I still think what we've seen in terms of resistance in Basra, Nasariyah, and Najaf are indicators of what we're likely to see in Baghdad, but on a much larger scale," says defense analyst Charles Pena of the Cato Institute in Washington.
By Thursday evening, US Army and Marine Corps units had pushed to the outskirts of Baghdad, preventing the destruction of bridges, securing highways, and in some cases fighting door-to-door in outlying cities. Special Operations forces raided the Thar Thar presidential palace about 56 miles northwest of Baghdad. They found no trace of Saddam Hussein or his sons, but seized important documents,
As US troops close with Iraqi forces in Baghdad, the danger of chemical weapons could decrease because of wind patterns and the difficulty of delivering them without harming Iraq's own soldiers.
Yet the possibility of biological weapons remains. Such weapons are harder to detect and easier to spread, and in the confusion of battle it's hard to know whether they're in fact weapons or some form of contagious disease.
"We could find ourselves bogged down, wading through and responding to a massive civilian sickness problem, fairly certain that it wasn't natural, but unable to conclusively pin it on Saddam," says former Pentagon strategist Larry Seaquist. "The Iraqis have quite a few choices of no-fingerprint diseases they might employ."
Still, much of this remains speculative. For one thing, the US-led coalition does not know who's running things in Baghdad.
"We can't tell who's in charge," says General Brooks. "I don't think the Iraqi people can tell who's in charge either, and we have indications that the Iraqi forces don't know who's in charge."
At times, it may be hard to remember that the war has been going on for barely more than two weeks. What was supposed to take 47 days according to the US war plan - reaching a point 50 miles south of Baghdad - took less than five days. No "scorched earth" policy - blazing oil wells, flooding caused by blown-up dams - has happened, as some had feared. Coalition casualties have been relatively light, given the overall force and amount of fighting. Civilian casualties have not been as bad as some had predicted.
But for all the speed of US forces northward, the resistance in southern cities has been greater than anticipated. And scenes of happy Iraqis showering coalition soldiers with garlands have been limited.
The coming humanitarian need - feeding, sheltering, and providing medical aid to hundreds of thousands, perhaps millions, of Iraqis is likely to be enormous. Helping build a democratic nation could take years, and could be undercut by possible attempts at an Islamist takeover as well as by questions about the size and independence of the Kurdish north.
For now, the goal is Baghdad. It could capitulate quietly.
Or it could prove to be the "Mother of All Urban Battles," as some warn.
"As the coalition gets closer to the city, the more urban the terrain becomes," says Colonel Smith. "And then you're back to the age-old question: How much of the city do you have to destroy to save it?"