The timing of the attack was extremely suspicious, but in retrospect, Clinton's decision to attack Iraq's military infrastructure in 1998 is probably a major reason that we did not find much in the way of Weapons of Mass Destruction in Iraq in 2003.
'Everyone' knows who Monica Lewinsky is. But not nearly as many know what Operation Desert Fox was. They happened at the same time, and the latter was thought by many to be nothing more than a cover by President Clinton of the scandal created by his involvement with the former.
Beginning on December 16, 1998, a three-day missile and bombing campaign, known as Operation Desert Fox, struck 97 separate sites in Iraq, most of which were believed to contain weapons of mass destructions, their precursors, and/or the facilities to create them. Some sites struck during the bombing were command and control sites.
At the time, President Clinton was being impeached. I thought, and many Republican politicians expressed their opinions that, the strikes were a way for Clinton to divert attention from himself. They really probably were, but the end result is interesting just the same. The strikes were probably more of a 'card up Clinton's sleeve'.
David Kay had been a senior weapons inspector for the International Atomic Energy Agency, and in 2003 entered Iraq as a representative of the United States with a fair amount of confidence that WMD would be found. Some of them may have been whisked off to other places, but not enough to make a huge difference. At any rate, WMDs were not found, and Kay counted himself among those surprised by this turn of events.
In reality, the timing was probably more fortuitous for Clinton than suspect. On December 15, 1998 a UN report stated that Iraq had failed to cooperate with the UN weapons inspectors. The next day, the US attacked. Coincidentally, a month prior to the strikes, Clinton hinted that Saddam Hussein needed to be replaced.
The results of the missile and air strikes was beyond anyone's imagination. It nearly had the single-handed effect of ruining the Hussein regime. In his book The Threatening Storm, Kenneth Pollack wrote:
Saddam panicked during the strikes. Fearing the his control was threatened, he ordered large-scale arrests and executions, which backfired and destabilized his regime for months afterward.
Intelligence sources in and around Iraq confirmed that there was "palpable fear that he was going to lose control." Ironically, a sentiment that was apparently completely lost on the Bush administration, leaders of other governments in the Middle East worried greatly at the prospects of Saddam's overthrow. You topple this guy, you'd better have a good plan in place, they said. Otherwise the whole region could descend into chaos.
Based on David Kay's research in 2003 in Iraq, his conclusion was that Desert Fox completely threw Saddam's WMD capability on its head. A high-level Iraqi energy official surrendered early on and explained that after 1998, Iraq had almost no ability to produce WMD's despite all of Saddam's bluster to the contrary.