The policy seems to be: if chemical weapons caches might support the policy of the president you hate, they don't exist. If ten years later you can use those same non-existent caches to pitch a "US bad to its own soldiers" story to your editors, well suddenly an ontological change occurs and those weapons become highly, highly significant.
Update: the more I think about this story, the more it burns me. I will let Gabriel Malor spell out why, but the gist is that Bush NEVER claimed Saddam had an active weapons program. Read the speeches again (they're linked at Malor's piece).
The first sentence is an absolute lie, uttered at Bush 43's expense, and made to justify the terrifying conclusion, laid at Obama's feet, in the last sentence.
This NYTimes piece has an overarching political goal: to cement forever the lie that the Iraq War was directed solely at stopping an active weapons of mass destruction program in Iraq. As we know, the military never found an active weapons program, which makes this a particularly compelling slander.
So let me remind you about the actual casus belli for the Iraq War.
In 2002, Saddam Hussein was doing everything he could to foil the UN weapons inspections teams about his existing weapons caches (the ones the NYTimes just "found" in its hit piece). You might recall, the U.S. was enforcing no-fly zones over Iraq at the time and attempting to ensure that Hussein remained disarmed. Hussein, for his part, was attempting to obscure both what he was capable of doing and what WMD, particularly biological and nuclear, remained to him. He was well-known, of course, for using chemical weapons against his own people and against the Iranians. Of particular concern going forward were his nuclear plans and the possibility that he would sell or give weapons to terrorists with Western ambitions.
On September 12, 2002, Bush went to the UN to plead with the useless world body to actually enforce sanctions and impose thorough weapons inspections. Nowhere in his speech will you find a claim that Hussein had an "active weapons program," as the NYTimes writers would now have you believe. Rather Bush talked about finding Hussein's old weapons and deterring his hope to once again restart his weapons programs