A Democrat, Mr. Guarini represented the ethnic polyglot that is Hudson County from 1979 to 1993, routinely winning re-election by 2-to-1 ratios. He chose not to seek an eighth term after his 14th Congressional District had been carved up in a redistricting. Earlier, as a state senator from 1966 to 1972, he played a central role in dismantling the long-entrenched Hudson County Democratic Party machine, Frank Joseph Guarini Jr. was born in Jersey City on Aug. 20, 1924, to Frank and Caroline (Critelli) Guarini. His father, a lawyer, was a state assemblyman in the 1930s. Mr. Guarini is survived by his sister, Caroline Mangin. His marriage, in 1954, to Audrey Berman ended in divorce. After serving in the Navy in the Pacific during World War II, Mr. Guarini completed his bachelor’s degree at Dartmouth College in 1947. He received his law degree from New York University in 1950 and soon joined his father’s practice. In recent years, he lived on Central Park South in Manhattan.