What I mean is from one of those old sayings from the foxhole: "If the enemy's in range....so are you."
When we're 10-15 miles out of Baghdad, then his artillery isn't going to make any difference. At that point our air assault, tank, and bradley chem. capability makes chemical control of chokepoints insignificant.
He's consolidating and getting rid of them.
I could make that argument about anything Iraq tried to do to stop our forces. But for WMDs to be effective (especially non-persistent agents), it makes sense to confine them to smaller areas. And the media would have ensured the public relations value of such WMD use would have been huge!
Saddam was planning a soviet style defense of Fortress Baghdad as in Fortress Stalingrad. He thought that the real fight will be in Baghdad where the US will suffer a lot of casualties there that will turn the public opinion against the war and force the US to withdraw. He failed miserably.