Francois Truffaut famously said it is impossible to make an anti-war film. This is cited numerous times by Ebert, and there is even the trope "Truffaut was right". But what is the source for this statement?
The earliest reference I could find was referenced in Truffaut: A Biography starting on page 163, 2nd paragraph.
This link starts on page 163 and gives the background. On page 164 there is the trope.
Truffaut never directly says "impossible to make an anti-war film." Rather in describing his desire to make one concerning Algiers, he decides that he cannot because "to show something is to ennoble it."
I found this quote today in a November 11, 1973 Chicago Tribune (pg 3e) interview Gene Siskel did with Francois Truffaut:
"I find that violence is very ambiguous in movies. For example, some films claim to be antiwar, but I don't think I've really seen an antiwar film. Every film about war ends up being pro-war."