If a Communist in disguis were to burrow into clerical circles and then very cleverly write a book aimed at disarming our country, but couched in the most pious terms of Christian morality, this could be it. Mr. Perla is certainly not a Communist, nor for that matter a Communist sympathizer, but he has an uncanny- and perhaps unconscious- ability to find solutions to world problems that would earn him medals from the Kremlin. Does he preach appeasement? No, he says, and requires a full chapter to explain why. He is merely preaching humility, justice, idealism, morality, and concession. But whatever label Mr. Perla puts his recipe for peace under, it still comes out with what seems a marked Moscow flavor. All in all, one has to admit this is an extremely clever book. The author begins by telling his reader that the time has come when we must stop making adherence to our foreign policy a test of patriotism. Once he convinces us that he is not really un- American, Mr. Perla then launches into a long critique of what he calls our ""double standard"" of morality. If Christian morality applies to us as individuals, he writes, then it should also apply to us as a nation. Ideally, of course, this means we must love our enemies. Translated by the author into practical action it amounts to recognizing Red China, seating her in the U.N., forsaking our allies and turning over Matsu, Quemoy and Formosa to our enemies. It also means closing down air bases and making concessions here and there. Appeasement? ""Christians should be outraged,"" writes Perla, ""to hear Christian doctrine contemptuously called appeasement, and adherence to those principles we profess, weakness and surrender."" What about getting a few concessions from the Russians? ""We cannot afford to wait for Russia to take the first step,"" argues Mr. Perla. ""Time is running out, and we have the greater obligation."" Whether or not time is running out is still a matter of opinion, and whether moral leadership compels us to betray our friends and love our enemies is again something many of us would like to think about further. To sum up- this seems a perverse use of Christian morality to weaken our nation's defense and subvert our instinct for self preservation.