WINSTON-SALEM, N.C. (AP) _ The death of former U.S. Sen. Sam J. Ervin Jr., the ''country lawyer'' who presided over the Watergate hearings that led to the resignation of a president, has cost the nation a ''towering historical figure'' who championed the Constitution.

Ervin, 88, died of respiratory failure Tuesday at North Carolina Baptist Hospital's Bowman Gray Medical Center, said hospital spokesman Roger Rollman. Kidney failure contributed to his death, Rollman said.

A critic of the civil rights movement and a supporter of individual civil liberties during his 20 years in the Senate, Ervin was hailed by former Gov. Jim Hunt as a man who ''loved the Constitution more than any man alive today.''

''He protected it during its time of greatest crisis and helped write history for our state and nation,'' Hunt said. ''He will truly be recorded as a towering historical figure and all North Carolina will forever be proud of him.''

Sen. Jesse Helms, R-N.C., who called Ervin his mentor, adviser on constitutional matters and friend, said, ''A giant has fallen ... I've never known a more remarkable American than Sam Ervin.''

U.S. District Court Judge John J. Sirica, who presided over trials involving the break-in at Democratic party headquarters in 1972 and the subsequent White House coverup, said: ''I was very fond of him and admired his patriotism, his dedication to his work and above all, his courage.''

Ervin's strict interpretation of the Constitution defied easy political classification. He sided with liberals and conservatives in becoming one of the chamber's most respected authorities on Constitutional law.

Ervin battled affirmative action proposals, the Equal Rights Amendment, surveillance of dissenters during the Vietnam War and efforts to return prayer to public schools.

For him, it was all the same battle - preserving the Constitution.

Ervin's independence made him a natural choice when Senate leaders sought a chairman for the sensitive and potentially explosive hearings on Watergate in the summer of 1973.To Ervin, the scandal that led to the resignation of President Richard Nixon was the nation's biggest tragedy since the Civil War.

''In the Civil War, there were many redeeming features of sacrifice and valor displayed on both sides,'' he said. ''But there was no sacrifice or spirit of sacrifice, or no valor, really, displayed on the part of those responsible for the Watergate hearings, except to sacrifice their character.'' However, he added, ''We do have this encouragement. We were able to weather the Watergate affair with all our essential institutions of government intact.''

During the Watergate hearings, ''Senator Sam'' T-shirts and buttons sprouted across the nation. But Ervin, his bushy eyebrows telegraphing moral indignation and blue-gray eyes twinkling at the onset of a joke, insisted he was ''just an old country lawyer.''

Ervin was born Sept. 27, 1896, in the foothills town of Morganton, one of 10 children.

His father, Samuel J. Ervin Sr., was a self-taught lawyer who ''hated the oppression of government, and I guess instilled in me the idea that, after all, the greatest threat to our liberties comes from government, not from others.''

After fighting in World War I and armed with a law degree from Harvard in 1922, he returned to Morganton and married Margaret Bell.

Burke County elected him to the state Legislature, where he helped defeat a bill that would prohibit the teaching of evolution in public schools, saying ''Such a resolution serves no good purpose except to absolve monkeys of their responsibility for the human race.''

For 25 years, Ervin interspersed public service with his law practice. He was a Superior Court judge from 1937 to 1944 and served in Congress in 1946 after the suicide of his younger brother, Joe.

In 1948, Ervin was appointed an associate justice of the state Supreme Court. He might have ended his public career as its chief justice but for the 1954 death of Sen. Clyde Hoey.

Gov. William Umstead, an old college friend, appointed Ervin to fill the seat and he was sworn in by then-Vice President Richard Nixon. He was re- elected later that year and thereafter encountered little opposition.

At the height of his fame and popularity in 1974, Ervin retired to his hometown. He said staying in the Senate until he was 84 would be asking too much of God and the people of North Carolina.

He wrote three books: ''The Whole Truth: The Watergate Conspiracy,'' ''Humor of a Country Lawyer'' and ''Preserving the Constitution: The Autobiography of Sen. Sam Ervin.''

He had two daughters, Leslie Hansler of Pennington, N.J., and Laura Smith of Morganton, and a son, Sam J. Ervin III, who followed in his footsteps and was named a judge on the U.S. Circuit Court of Appeals.

Ervin said he tried to heed Shakespeare when confronted with a choice between his own conscience and politics: ''To thine own self be true, and then it must follow as the night the day, thou canst not then be false to any man.''

Services will be Friday in Morganton.