Eric Sevareid once said of her that she ""gave rudeness a new dimension,"" and when Ike was president Sarah McClendon was accused of personally contributing to his high blood pressure. But official Washington is evidently very fond of the bluff, independent woman who asks questions ""from a different wavelength."" McClendon, who's been at the job since before World War Il, explains that it's because she's her own one-woman news service in D.C., representing the local and regional press (Waco News-Tribune, Port Arthur News, San Antonio Light, and their New England counterparts). She's liable to ask a President about surplus cabbages for Appalachia, tin smelting, or the shoe industry, and tends to leave the more cosmic issues to the wire services and the networks. Still, by her own account she helped to break the Bobby Baker scandal (which, she feels, could have forced Johnson to resign), rooted out two highly suspect individuals from the State Department, and lobbied to unsnag red tape in the Veterans Administration. ""You have the loudest voice, you go right ahead,"" said Nixon at one press conference, and McClendon marches right in where angels fear to tread. But she's not all brashness by any means, and her book also contains fond presidential mementos--of Johnson who drove his car at 95 m.p.h, on his Texas ranch, of JFK (""I adored him""), and of Carter for whom she holds high, high hopes. Pert and wholesome, she makes a nice contrast to the D.C. ultra-sophisticates.