Wherever your attention wandered these past two weeks, it was all but impossible to avoid the posturing of Admiral General Aladeen — i.e., Sacha Baron Cohen, in full regalia. There he was at Royal Festival Hall in his orange Lamborghini, wielding a golden pistol, and on Jon Stewart’s show, accompanied by his virgin bodyguards (yes, even Stewart acceded to Sacha’s demand to be interviewed as his movie character).Sacha has made the media rounds now as Ali G., Borat and Bruno, stubbornly refusing to appear as Sacha, which has led many to ask, is there really a Sacha Baron Cohen? I’ve met Sacha often enough now to conclude that it’s a legitimate question. (By the way, his movie, “The Dictator,” is either hilarious or numbingly flat, depending on which scene you’re watching.) Sacha’s personality disorder (if that’s what it is) provides a flashback to another mythic name that was in the news last week, Johnny Carson, the King of Late Night. A superb “American Masters” documentary on Carson reminds us how, during his 30-year reign, Carson would be consistently charming and accessible before the cameras, only to disappear into a shell once his last TV guest said bye-bye. Given his marginally bipolar personality, those in Carson’s tiny inner circle were not surprised when he engineered his total disappearance once his show went off the air. I was lucky enough to have dinner with Carson a couple of times and came away feeling that, as with Sacha, his TV persona represented an invented character — one he did not wish to tug around in his personal life. Carson impressed me as an extremely thoughtful and intelligent man who skillfully kept his demons under control. Nonetheless, when his favorite substitute host, Joan Rivers, decided to do a competitive latenight show without first informing him, Carson resolutely but silently slammed the door on her, never mentioning her again. I’ve also been treated to an occasional glimpse of the private Sacha and even persuaded him once to do a live show before an audience — with Sacha as Sacha. Stripped of his outrageous cover (he was promoting “Bruno” at that time), he seemed uniquely uncomfortable in advancing his own opinions — so much so, that he came across as intentionally bland. The real Sacha, I am told, is brilliant and well read, comes from an orthodox Jewish background and is extraordinarily difficult to work with on a professional level. That’s because colleagues must deal with the demands not only of Sacha but of the bizarre personalities whom he becomes. In “The Dictator,” Sacha has helped concoct a bawdy political farce that, unlike “Borat,” is scripted — much of it clumsily. Sacha’s performance is inspired — A.O. Scott of the New York Times calls him “a cross between a camel and a chameleon” — except when his character is supposed to have a love interest (women in Sacha’s movies are laughable, not lovable). Filmgoers willing to sit through the dead zones will relish the vulgar hilarity, as well as the political message — what other movie is dedicated to Kim Jong-il and sprinkled with Dick Cheney jokes? But will Sacha Baron Cohen be able to build a career around a succession of outrageous characters, appearing in public only as his alter egos? Will he abandon the brilliant pseudo docu style of “Borat” for scripted roles? (He had a part in “Hugo.”) In short, will the real Sacha Baron Cohen ever “come out?” During his amazing career, Johnny Carson remained brilliantly self-protective, retaining his on-camera persona, but that was before the era of TMZ-style reporting that would have magnified his divorces and other secret neuroses. Sacha Baron Cohen is a provocateur, of course, not a host. He is the manic Admiral General Aladeen, the despot of Wadiya in North Africa who is obsessed with his nukes as well as with his virgin bodyguards. Can an actor who wallows in comedic chaos remain invisible?