About 150 Capitol Hill colleagues, friends and admirers gathered yesterday to pay final tribute to Sam J. Ervin Jr., praised as a man of courage, vision, integrity and an overriding sense of duty to his country.

At a memorial service for the late North Carolina senator at the National Presbyterian Church, Ervin was lauded for his role in two constitutional crises -- the McCarthy era and the Watergate scandal -- and praised as a constitutional scholar whose contribution to the Republic would have been enormous in any event.

Ervin died April 23 in Winston-Salem, N.C., at age 88.

Among those attending yesterday's service were Sens. Russell B. Long (D-La.), Sam Nunn (D-Ga.) and Lawton Chiles (D-Fla.); former senator Harry F. Byrd Jr. (Ind.-Va.); Rep. James T. Broyhill (R-N.C.); former representative Horace Kornegay (D-N.C.); Sam Dash, chief counsel for Ervin's special Watergate investigating committee; and Prof. Philip Kurland of the University of Chicago Law School.

"History will emphasize his role in two critical episodes," Kurland said. "He helped halt the threat to our freedoms posed by McCarthyism, and -- if temporarily -- helped stem the 'Imperial Presidency' during what we came to call Watergate."

Kurland said Ervin was "one of the few who were bigger than the office they held."

"In my years of study of the Constitution and the writings and arguments of the Founding Fathers, I came to realize that Ervin's voice was that of James Madison, . . . Benjamin Franklin and George Mason," Kurland added. "He understood that the Constitution and the Bill of Rights were the keystones of our freedoms, of a system where officials could not mock justice and are under the rule of law."

Broyhill noted the tough job Ervin took on as chairman of the Watergate panel in 1973.

"They couldn't have picked anyone better for keeping our political institutions intact in those times," Broyhill said. "Even without Watergate, he would have gone down as one of the nation's leading constitutional scholars."

Kornegay said the country had lost "a great statesman and a beloved citizen" who retained his native modesty even with the accolades that followed his Watergate service.

"He told me once that they were a source of some embarrassment to him," Kornegay recalled. "He said, 'When I hear all those kind words, I feel people have come down with a severe case of mistaken identity.' "

Byrd said that political courage is rarer than physical courage, and that Ervin had more than his share of both.

"As a young man, he was twice wounded and won the Distinguished Service Cross," Byrd said in a reference to Ervin's service in World War I.