A quarter-century ago, Newark and nearby Union City epitomized the failure of American urban school systems. Students, mostly poor minority and immigrant children, performed abysmally. Graduation rates were low. Plagued by corruption and cronyism, both districts had a revolving door of superintendents. Today, Union City, which opted for homegrown gradualism, is regarded as a poster child for good urban education. Newark, despite huge infusions of money and outside talent, has struggled by comparison.