Being one of the defining moments of that war, there has to be evidence of it online. It's been referenced in movies and books, but I have not seen it, nor have my many searches turned it up.
I'd like to see video specifically, of the legendary moment where he supposedly steps from behind the news desk for the first time, points at a map, and says something along the lines of, "This is not winnable." Or to that effect.
Walter Cronkite CBS News broadcast Feb. 27, 1968, as quoted by NPR
"Both in Vietnam and Washington to have faith any longer in the silver linings they find in the darkest clouds. For it seems now more certain than ever, that the bloody experience of Vietnam is to end in a stalemate. To say that we are closer to victory today is to believe in the face of the evidence, the optimists who have been wrong in the past.
To say that we are mired in stalemate seems the only realistic, if unsatisfactory conclusion. On the off chance that military and political analysts are right, in the next few months we must test the enemy's intentions, in case this is indeed his last big gasp before negotiations.
But it is increasingly clear to this reporter that the only rational way out then will be to negotiate, not as victors, but as an honorable people who lived up to their pledge to defend democracy, and did the best they could."
The video: