When I told some colleagues that I, a conspicuous Protestant, thought I should say a word in this sulfurous climate on behalf of a brother cleric, I was advised against it and told that every angry Catholic and militant secularist in town, not to mention the unbridled forces of the city media, would be against me.The question was sharply put: ''Why would you support a man who has lost all support?'' The answer is simple, at least in my profession: ''Because he needs it.''I cannot imagine what breakfast at the cardinal's residence on Lake Street must be like, with the table laid with the morning edition of the local papers. The news is bad enough, but when columnists and editorial writers weigh in with their shrill characterizations and cries for arch-episcopal blood, one cannot help but empathize just a bit with the Nixon-like figure who is damned at every turn. Those who not long ago were pleased to be pictured with the cardinal, kissing his ring and attending his charitable events and proud to be known as archdiocesan insiders, now, like the disciples on Maunday Thursday, have forsaken him and fled. If a public figure is treated like Nixon, we shouldn't be surprised if he behaves like Nixon, to whom Norman Cousins, in The Daily Telegraph of July 17, 1979, ascribed the motto: ''If two wrongs don't make a right, try a third.''