Dale Bumpers, a former Arkansas governor and U.S. senator who earned the nickname "giant killer" for taking down incumbents, and who gave a passionate speech defending Bill Clinton during the president's impeachment trial, has died. He was 90.

Bumpers died Friday night in Little Rock, according to his son, Brent Bumpers. Bumpers was under hospice care and died due to natural causes and complications from a broken hip suffered in a recent fall, his son said.

Bumpers was a little-known lawyer from Charleston when he ran for the Democratic gubernatorial nomination in 1970, against a field that included former Gov. Orval Faubus. After finishing second in the primary, Bumpers defeated Faubus for the Democratic nomination -- then beat Republican incumbent Gov. Winthrop Rockefeller in the general election.

Four years later, Bumpers challenged and defeated incumbent Sen. J. William Fulbright in a Democratic primary, and went on to win the U.S. Senate seat.

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Bumpers' signature moment on the national stage came in 1999, just weeks after leaving the Senate, when he defended Clinton -- who had worked for Fulbright's 1974 campaign against Bumpers -- before the U.S. Senate during his impeachment trial.

Clinton had been impeached by the House on charges of lying about his sexual relationship with Monica Lewinsky while testifying before a grand jury in the Paula Jones sexual harassment case.

Bumpers called the matter a sex scandal while delivering the closing argument as the Senate considered removing Clinton from office.

Clinton "suffered a terrible moral lapse, a marital infidelity. Not a breach of the public trust, not a crime against society," Bumpers said. "H.L Mencken said one time, 'When you hear somebody say, 'This is not about the money,' it's about the money ... And when you hear somebody say, 'This is not about sex,' it's about sex.'"

Clinton was acquitted by the Senate.

Bumpers would later say that he didn't want to give the closing statement, but Senate leaders and Clinton asked him to do so.

A statement from Clinton and Hillary Clinton did not mention the impeachment, but praised Bumpers' work as governor and senator.

"For more than 40 years Hillary and I cherished his friendship. I am grateful that his advice made me a better governor and president," Clinton said. "I loved him. I loved learning from him and laughing with him. I will miss him very much."

Bumpers had been known in the Senate for his oratorical skills, as well as his opposition to amendments to the U.S. Constitution, including one that would prohibit busing of public school students.

Brent Bumpers said he believes his father would want to be remembered as both a champion of the underdog and a defender of the Constitution.

"He often listed that as among his proudest battles, he fought against many efforts to amend the Constitution. He revered it so much," Brent Bumpers said.

Bumpers was considered a potential Democratic candidate for president in 1980 and 1984, but declined to run. He would later say he believed his best chance at winning the presidency had been in 1976, when Georgia Democrat Jimmy Carter won the White House.

Bumpers also was an attorney for the Charleston School Board in 1954 when the board voted to integrate, two months after the U.S. Supreme Court's landmark Brown vs. Board of Education ruling that outlawed segregated schools, It was the first district among the 11 former Confederate states to integrate.

"We did it because we thought it was the right thing to do," Bumpers told The Associated Press in 2007.

Bumpers had won re-election to the Senate in 1986 by defeating current Gov. Asa Hutchinson, a Republican.

"The entire state mourns the loss of an Arkansas legend," Hutchinson said in a statement Saturday. "In my first statewide race, Dale took me to school on Arkansas politics. He was a master storyteller, and his stump speaking was impossible to beat."

Six years later, Bumpers defeated future Arkansas governor and current Republican presidential candidate Mike Huckabee for re-election.

"I first knew him as a political opponent and I must confess he beat me like a drum," Huckabee said in a statement. "Our political differences aside, he was a dedicated public servant who always reminded his audiences that 'public service is a noble calling.'"

Former Gov. Mike Beebe, a Democrat, called Bumpers a friend and mentor.

"Dale's passion for good policy and responsible government brought opponents to common ground and inspired the detached to become involved citizens," Beebe said.

Bumpers is survived by his wife, Betty Bumpers, two sons and a daughter. Funeral services are pending.