When your driver suggests you don a Kevlar (search) vest for the ride in from the airport, you know you're not in Kansas anymore.

You're likely in Baghdad. Though conditions have improved immeasurably in the six months since Saddam Hussein's blood-soaked reign, there is enough uncertainty about security to make Iraqis and foreigners alike treat every loud pop from behind like a mugger with mayhem in mind.

Not everyone has access to the bulletproof vest I was given on arrival in the capital. I was just one of the lucky ones.

On Tuesday, three small rockets hissed across the Tigris River (search) and into the so-called "Green Zone" (search), where American control, though tight, is evidently nowhere near perfect. The whump-whump blasts into the heart of the U.S. compound sent Americans inside scurrying for cover, and damaged some vehicles in a parking lot, though there were no immediate reports of injuries.

It was a day of trying to put together the pieces in Iraq, of trying -- perhaps in vain -- to make sense of the apparently random attacks that have claimed 155 servicemen's lives since May 1. The attacks seem to come from nowhere, at various times and in different circumstances. They must be launched by someone. Who?

The riddle is slowly being solved. First, Lt. Gen. Ricardo Sanchez (search), the chief commander of U.S. forces in Iraq, revealed that coalition forces have been holding as many as 20 suspected members of the Al Qaeda (search) terrorist group in Iraq. Sanchez conceded, though, that there was no final evidence to make the link between the suspects.

A more direct link came the same day, from Abdul Aziz al-Hakim, a member of Iraq's Governing Council. Visiting Kuwait, al-Hakim said Al Qaeda militants have slipped across from Saudi Arabia, whose capital suffered a devastating bomb attack this weekend, to Iraq. "We had feared that Iraq would turn into a breeding ground for terrorism," said al-Hakim. "We expect those operations which took place in Riyadh have a link to the terrorist groups inside Iraq."

Al Qaeda foreigners or Iraqi nationals with a grudge against the American Army that liberated them from Saddam? It matters, of course. If Al Qaeda has, indeed, decided to turn Iraq into its new battlefield, the U.S. war on terror could quickly take a new and streamlined look, a refinement from occupation to pure terrorist mop-up.

If Al Qaeda is in Iraq to do evil, then the U.S. belongs here to wipe it out before it happens. That kind of mission, properly defined and explained, would likely win wide support among an American populace unsure just what troops are doing in Iraq.

To those who endure the pummeling of sudden shells, the whistling of invisible ordnance, the distinction is largely academic. Whether the victims are Iraqi or American, civilians or soldiers, the mood of anxiety they create in Baghdad works in favor of chaos.

The encouraging news is that even as they continue, their authors are showing their hands, and their origin and identities come into focus. The times are tense, to be sure, but time is on the side of the coalition, which is getting better at what it does, even as the rockets rain down.

John Moody is senior vice president of Fox News.