The Pentagon says it is only a matter of time before Saddam Hussein's regime collapses. But while coalition military operations appear to be going smoothly thus far, defense officials are bracing for possible trouble.
It is only about 500 kilometers from the Kuwaiti border to the Iraqi capital, Baghdad. Yet in just three days, allied forces have crossed the Euphrates River and pushed halfway there, a rolling wave of soldiers and steel backed by a massive display of airpower.
Senior military officials attribute the impressive speed of the advance in part to the lack of significant resistance. Engagements so far have been limited and settled rapidly. Thousands of Iraqi soldiers have surrendered or simply deserted. Iraqi combat vehicles and weapons have been found abandoned.
Coalition troops have also not been confronted yet with any chemical or biological weapons. Not a single Iraqi Scud missile has been fired. Yet there are concerns that perhaps the toughest road is the one that now lies ahead.
Pentagon officials have long believed that resistance to the invasion is likely to be stronger the closer U.S. led forces get to Baghdad. That is where most of Saddam Hussein's toughest soldiers are located, troops like the Special Republican Guard.
Major General Stanley McChrystal of the Pentagon's Joint Staff admits that significant Iraqi forces are in front of the advancing wave of allied tanks, armored vehicles and other heavy equipment now speeding north. He also says the coalition is still respectful of the capabilities the Iraqi military has, including air defenses around the capital and what the Pentagon says are the regime's well-hidden though still yet unseen weapons of mass destruction.
The general and Pentagon spokeswoman Victoria Clarke say that as successful as Operation Iraqi Freedom has been thus far, the situation remains both highly fluid and extremely dangerous, even though they insist allied bombing has severely degraded the Iraqi leadership's ability to command and control Iraqi forces.
The Pentagon still says it has no definitive word on the fate of Saddam Hussein and cannot say whether Saddam or any other senior leader is able to direct Iraqi troops on a day-by-day basis.
But officials still appear to hope for a breakthrough in Baghdad, one that might be achieved well before coalition armored columns reach the city's outer limits.
Discussions continue in secret aimed at bringing about the capitulation of Iraqi military commanders. And Defense Secretary Donald Rumsfeld has signaled his hope that if Saddam Hussein is alive, then perhaps aides may either assassinate him or force him into exile or even turn him over to the coalition.
In the meantime, though, despite the speed of the allied advance from the south, no one is willing to predict just how much longer it will take for coalition troops to reach Baghdad, especially following the collapse of the U.S. plan to increase the pressure on the capital by deploying a large, armor-backed ground force into northern Iraq through Turkey.
Nevertheless, U.S. officials insist there will still be a northern front, important for securing Iraq's northern oilfields. But little is known about military activities there beyond the presence of elite Special Operations units.