Drop the premature conclusion that if we can't yet find proof of the destructive weapons, they never existed. That's like saying because we haven't found Osama or Saddam, those killers never existed.
Now, we must first mention that Safire just ripped these words -- uncredited -- from the mouth of Donald Rumsfeld ("Well I like to do my own research so I think what I would say is that we haven’t found Saddam Hussein and I don’t know anyone whose running around saying he didn’t exist.") and the logic behind them hasn't improved with use. Bullshit is not a baseball mitt.
Think about what he's saying here: Saying that something doesn't exist because we can't find it is like saying that something else doesn't exist because we can't find it, either. The difference, obviously, is that everyone's seen Saddam Hussein and no one had to trump up any intelligence to prove he was there. It's that simple. By Safire's logic, you could replace "destructive weapons" with anything -- pixies, the Loch Ness Monster, a Republican with a conscience -- and we have just as much reason to believe they exist as a person we saw on the news last night.
Update: Via (that other) Roger Ailes, I notice that Casper Weinberger has been making the same argument.
That we have not yet located huge deposits of weapons of mass destruction does not mean they do not or did not exist. After all, we have not yet found Saddam Hussein or his remains--but not even Democratic presidential candidates or the New York Times contend that he did not exist.
Dumbasses. They should all really coordinate their use of these appeals to ignorance. If you use them all up on the same weekend, where will you be when the president's poll numbers are in the low 40s? Like October.
Again: Bullshit is not a baseball mitt.