The Trinity and Avodah Zarah

I had an idea to put and end the debate whether or not Christianity is Avodah Zarah or not. I heard quoted in the name of the Rav that there are two types of safek: The one where there is a lack of information (Safek more than 1/60 of milk landed in the roast or not) then there is the lack of decipherability (twilight is safek yom, safek layla). From the minimal study of Christianity it appears that the safek whether or not Christians believe in one or three deities is really the latter form of safek (this is to completely skirt the issue of comparative religion). One is three and three is one, sort of like bein hashmashot is both night and day. Then we can just apply our nifty safek deoryta lechumra approach and be done with it. Does someone already bring this down?