Inventively plotted but starchily padded and only marginally involving, this suspense contrivance imagines a Soviet plot to install Russia's own puppet Pope in the Vatican. The central gimmick: Czechoslovakia's Cardinal Michalovce was secretly married (to ""a Jewess no less!"") during WW II--information which the KGB has passed along to the Soviet Chairman; so the Cardinal must do Russia's bidding or be exposed. But how to arrange for Michalovce to be elected? Well, Russia dispatches a super-agent called ""the Professional"" to Rome: he kills a newly arrived priest, dismembers the body, and assumes the priest's identity (an art restorer at the Vatican); he arranges to murder the current, recently elected Pope by kissing his hand with nicotine (though the Pope conveniently keels over from natural causes); and, before the conclave gathers to elect a new Pope, the Professional sneaks in and rigs the balloting--via silicone (moveable) ink and a hidden oscillator which activates the magnetic threads in the pre-marked ballot cards. Meanwhile, however, two forces threaten the scheme's success. Roman cop Barzini is determined to solve the case of that dismembered, unidentifiable priest--an investigation which picks up steam when the Professional commits similar mayhem on two of his accomplices (whom he needed to help him maintain his art-restorer credentials); Barzini will eventually track the killer right to the Vatican, where (far too coincidentally) he'll stumble on the evidence about Cardinal M.'s past. And there are also plottings by the Soviet Chairman's chief rival, who wants to foil this Chairman-enhancing scheme. So finally, after Cardinal M. is indeed elected, there'll be a Barzini/professional showdown-chase. . . and the murder of the brand-new pope by the anti-Chairman forces. Klausner (Son of Sam, p. 61) does a competent job--despite many implausibilities--with the scheme itself, with Barzini's legwork, and with the many killings. The principal characters, however, are uniformly unengaging as Klausner's focus revolves predictably; each small plot development is stretched out pointlessly; and the serviceable prose sometimes slips into pulp-mag style (""the machinations of power-mad mortals. . . a more devious and manipulating menace lurked unseen""). A just-passable thriller, then, with a few cinematic possibilities.