Reading Mary McCarthy on her month's visit to Vietnam earlier this year is like turning on TV and confronting a split screen: in one half, Uncle Sam with candy in his pockets; in the other, a woman crying that she'd rather be dead; the caption--pacification. What this word-wise observer found beyond barbarism (Saigon ""a gigantic PX,"" the countryside littered with indestructible mass-production garbage) was organized semantic obfuscation: a ""constructed"" hamlet is one newly purged of VC, ""Rural Development""' being the process thereof; a bomb planted by the VC is an ""atrocity,"" a village bombed by Americans is an ""accident."" Worse, the truth revealed by these transparent subterfuges is invisible to their perpetrators. The reporter sees misery and squalor in refugee camps; the social critic is fascinated by the cynical American colonel, University of Chicago-trained political scientist, who manipulates a village like a toy in his hand. In a final chapter called ""Solutions,"" Miss McCarthy avers that none of the dissenters--Schlesinger, Galbraith et al--oppose the war enough to stop thinking in terms of ""solutions"": we should determine to get out and let those who are there figure out how to do it. All but the last appeared in The New York Review of Books; it merits wider exposure.