Unlike, say, for Joe Klein* or numerous others who kept their traps shut during the run-up to the war, I think it would be quite possible for Bill Clinton to have opposed the Iraq war in his heart but to have kept his trap shut due to the inconsistently observed but somewhat valid tradition that ex-presidents pull back a bit from politics.
But the quote below demonstrates that Clinton was proud of his role in opposing the opposers, in battling the Fearsome Left.
*Except that time when Joe said he supported the war, of course.
