But the two cities share few similarities and the thinking at the Pentagon is that the southern port of Basra will be far easier to capture for the U.S.-led coalition. Baghdad, Iraq's capital, is home not only to many of Saddam Hussein's main palaces but also his Republican Guard and other security forces.
Basra is up first. Just 35 miles from the Kuwaiti border, the city of about 1.3 million is Iraq's main seaport and a key center for its oil industry. The city was devastated by fighting — including Iraqi chemical weapons attacks — during the 1980-88 Iran-Iraq War, which was fought mainly over the Shatt al-Arab waterway that connects Basra to the Persian Gulf.
Pentagon officials say Saddam does not appear to be planning to put up much of a fight for Basra. The city is protected by two regular army divisions, not Saddam's relatively well-equipped, trained and trusted Republican Guards.
The regular army troops are unlikely to fight hard, if at all, Pentagon intelligence officials say. Most of the city's population is Shiite Muslim — a group that rebelled against Sunni Muslim Saddam and his Sunni-dominated government in 1991 after the Persian Gulf War.
Military officials say they hope that anti-Saddam feeling in Basra could prompt the city's troops and residents to welcome coalition troops as liberators, providing a psychological blow to troops and government officials in Baghdad.
Chemical weapons are a looming question mark, however. Pentagon officials say there's evidence Saddam has given field commanders authority to use chemical weapons on their own initiative and may have moved chemical weapons to units south of Baghdad.
The Iraqi military commander for the region including Basra is Saddam's cousin Ali Hassan al-Majid, known to his enemies as "Chemical Ali" for leading the 1980's campaign against rebellious Kurds that included chemical weapons attacks that killed thousands of civilians.
Soon after the war starts, U.S. and British forces in Kuwait probably would dash across the border to capture and hold Basra, aiming to prevent chemical or conventional attacks on the troops massed in Kuwait and securing the area so Iraqi forces there could not attack the coalition forces advancing on Baghdad.
British media reports say the United Kingdom's troops are likely to get the task of holding Basra, a job the British have done before. Britain invaded Iraq through Basra in May 1941 to oust an Arab nationalist and pro-Axis government, which the British accomplished by the end of that month.
Baghdad will be a much greater challenge to the U.S.-led forces. A sprawling city of more than 5 million people, Baghdad has a relatively sophisticated air defense network and is surrounded by three Republican Guard divisions. Saddam's Special Republican Guard of 10,000 to 12,000 troops is in Baghdad, as well as tens of thousands of his security forces.
Iraqi forces already have built trenches and mounds on the outskirts of the city, reinforced some troop positions with sandbags and poured oil or gasoline into trenches or canals to set fires in an attempt to thwart U.S. airstrikes with a thick smoke screen. Pentagon officials say those tactics will amount to little more than a "speed bump" for U.S. forces, which rely heavily on satellite-guided munitions unaffected by smoke.
Still, urban combat in Baghdad could be deadly for Iraqi civilians, dangerous for the U.S. troops and harmful to America's image worldwide. If enough loyal Iraqi forces disperse throughout the city and hole up in civilian areas, the resulting street fighting would be a deadly haze of confusion.
American troops have entered that haze before, in the battle for Seoul in the Korean War, while fighting in Hue during the Vietnam conflict, and in the disastrous 1993 raid in Mogadishu, Somalia.
In addition to the risk from enemy fire, Americans could also be in greater danger of dying from friendly fire when they enter cities. In the first Gulf War, one-fourth of the Americans killed in combat were killed by other Americans, reports CBS News National Security Correspondent David Martin.
How much resistance to coalition forces there would be in Baghdad is impossible to predict. The Pentagon has advantages in night-vision equipment, satellite imagery, communications and weapons. American troops have fiber optic scopes to see around corners and small, remote-controlled airplanes with video cameras to get live, overhead views of an urban battlefield.
"Most Iraqi government facilities and key strong points are in large, exposed compounds," Iraq expert Anthony Cordesman of the Center for Strategic and International Studies wrote earlier this month. "They can be totally destroyed from the air with little fear of civilian casualties and collateral damage."