I've just finished listening to the director's commentary for this film, and I think the one big thing I got from it that I agree with is that this film, like Mann's The Insider, is completely subjective. It's from Howard's POV. So, any review or attempt at contemplating a set of comments about it, as Ebert did, is really about Nolte's character actually. If you feel, as he did, that the film "does not work", then you're saying, I think, that Howard does not work. And, to be frank, you might be right. Howard's reasoning and personality really wouldn't stand up to professional mental treatments and analysis.
But, hey, that's the nature of people.
Andrew.

The main reason people still care about "Carlton-Browne Of The F.O." is that it features Peter Sellers in a second-billed role. But watching this film to see Peter Sellers is a mistake.
Sellers plays Amphibulos, a vaguely reptilian prime minister of the dirt-poor island nation of Gaillardia, formerly a British colony, now hosting a lot of Russian diggers during the height of the Cold War. Amphibulos wants to play both U.K. and Soviet interests against each other for easy profit, "everything very friendly and all our cards under the table". Terry-Thomas is the title character, a lazy British diplomat anxious to show Gaillardia that Great Britain hasn't forgotten them, all appearances to the contrary.
A positive review here says: "The reason this movie is considered average is because the comedy is understated." I would argue that the reason "Carlton-Browne" is considered below average is because the comedy is non-existent.
After a decent opening that establishes the film's only two strengths, a sympathetically doltish Terry-Thomas and John Addison's full-on larky score, things quickly slow down into a series of slow burns and lame miscommunication jokes. The low opinion of Carlton-Browne by his boss and the obscurity of Gaillardia (which no one can find on a map) is milked to death. By the time we actually reach the island (after a labored series of airsick jokes), expectations are quite low.
They're still too high, though. The island itself, which seems to exist either in Latin America or the Mediterranean, is so pathetic its honor guard faints at the airport, and the review stand falls apart in the middle of a parade. The army is apparently still horse drawn, allowing for another lame aural gag by a thick-accented announcer: "In war, the army uses many horse."
Sellers never quite takes center stage even when we're on his character's island. The plot is taken over instead by Ian Bannen as King Loris, who inherits the throne of Gaillardia after his father's assassination. Bannen is dull and plays his part as straight as it is written. Normally this would make him the likely target for scene-stealing by Sellers, but trapped behind a thick accent and greasy moustache, Sellers is only a threat to those of us who remember him far more happily in two other films made this same year, "The Mouse That Roared" and "I'm All Right, Jack."
Strange that this film, like "Jack", was a Boulting Brothers production, with Roy Boulting here serving as co-director alongside Jeffrey Dell. Usually Boulting films combine wicked social satire with anything-goes comedy, but here there are only fey jabs in either direction. Amphibulos works his mangled-English vibe for all its worth ("This man is like, how do you say, the bull in the Chinese ship") while Carlton-Browne is generally ragged on by his superior far more than he seems to deserve.
The weakest and most protracted element of the film is young Loris's romance with Ilyena. Score one point for her being played by ravishing Luciana Paluzzi, dock one for the fact that they are apparently cousins is never addressed.
The film winds up with a lamely staged revolution whose surprise resolution will surprise no one, and a final bit of action by Carlton-Browne that would seem to nail the lid on his coffin literally. Apparently he lives to see another day, but the film of the same name is strictly DOA.