CHICAGO -- ''Starships'' is the song that caused Nicki Minaj a heap of trouble. At Hot 97's Summer Jam last month, Ms. Minaj withdrew from the concert after one of the radio station's D.J.'s, Peter Rosenberg, derided that song as too pop, and also derided its fans, more or less for being too female. It was an awkward, unfortunate exchange between hip-hop's competing poles of traditionalism and experimentation. It was even more awkward because, more so than almost any other current rapper, Ms. Minaj can operate successfully at both extremes -- she's a top-notch rapper when she chooses to be and a flagrant rewirer of hip-hop orthodoxies much of the rest of the time. Her liminal status was what was really on trial. ''Starships'' was just a sacrificial jam. [ABSTRACT FROM PUBLISHER]