According to an Iraqi official Saddam didn’t have WMD’s but couldn’t admit that he didn’t have them because he would look weak in front of fellow Arab leaders. He also thought that pretending to have WMD’s would prevent a US attack.
The official was not in the top rank of the Iraqi leadership nor does he want to be identified so his story isn’t neccessarily automatically believable but as the months wear and WMD’s aren’t discovered in as much profusion as originally thought this explanation of Saddam’s behaviour may be granted more importance.
There’s a certain irony in this of course. It would have been much more difficult, if not impossible, for the US and Britain to go to war without the threat of WMD’s. If Saddam didn’t have them but indulged in macho posturing to pretend he did he’s responsible for one of the more spectacular diplomatic blunders of the last couple of centuries.