Nearly a half-century ago, the U.S. Supreme Court ruled that the right to counsel is so fundamental that an attorney must be provided at state expense for a poor defendant who cannot afford his own lawyer. William J. Leahy, 64, has spent his entire legal career striving to give reality to the promise of Gideon v. Wainwright, 372 U.S. 335.

A 1974 graduate of Harvard Law School, Mr. Leahy worked as a public defender, deputy chief counsel and, for 20 years, as the chief counsel of the Massachusetts Committee for Public Counsel Services, a state agency providing representation to 265,000 indigent clients annually through 265 state attorneys and 2,900 assigned public lawyers. The agency had a $202 million budget last year.