WASHINGTON (Reuters) - Former U.S. Senator Thad Cochran, the courtly Mississippi Republican who held leadership positions over some four decades in the Senate, died on Thursday at the age of 81, his successor, U.S. Senator Cindy Hyde-Smith, said in a statement.

FILE PHOTO: U.S. Senator Thad Cochran takes part in a news conference at the U.S. Embassy in Havana, Cuba, February 22, 2017. REUTERS/Alexandre Meneghini

Cochran had served as chairman of the influential Senate Appropriations Committee, which controls billions of dollars in discretionary spending, and before that during the George W. Bush administration, when he oversaw funding for the Iraq War and rebuilding after Hurricane Katrina hit the U.S. Gulf Coast.

He resigned from the Senate last year due to health concerns. Hyde-Smith was first appointed to take his seat, and won a special election last November to serve the remainder of his term.

Cochran started out as a Democrat back when the U.S. South was a stronghold for the party, and voted for Lyndon Johnson for president in 1964. But with the region shifting toward the Republican Party, four years later he worked for Richard Nixon’s successful presidential campaign.

Cochran first went to Washington to serve in the U.S. House of Representatives in 1973. When he was elected to the Senate in 1978, he became the first Republican to win a statewide election in Mississippi since Reconstruction following the Civil War.

His health had been a concern for several years and there was increasing speculation in 2017 that he might have to step down at a time when Republicans needed all the Senate votes they could get in pushing for tax breaks and undoing Democratic former President Barack Obama’s healthcare program.

Cochran had survived an especially nasty 2014 re-election race after insurgent right-wing Tea Party Republicans went after him as the embodiment of establishment Washington. The opposition campaign accused Cochran of having an affair while his wife, Rose, was suffering from dementia and published photos online of her in a nursing home bed.

Despite his positions of power, Cochran kept a low profile in Washington - not the sort to appear on Sunday political talk shows to discuss hot issues. He also had a reputation as a Republican who was not averse to working with Democrats.

U.S. Senator Chuck Schumer, the chamber’s top Democrat, called Cochran “one of the most personally decent, nicest people” he had met in his career.

President Donald Trump called Cochran a friend, and wrote that he “never let our Country (or me) down!” in a Twitter post.

HEALTH PROBLEMS

Cochran had a dwindling presence in Washington in 2017 after contracting a urinary tract infection that kept him in Mississippi for several weeks in the fall as Republicans formulated spending bills to keep the federal government running late in the year.

He frequently missed votes, and media reports said he rarely met with colleagues and was showing mental and physical deterioration. In October 2017 Politico reported he appeared disoriented in the Capitol and mistakenly cast a “yes” vote on a tax reform amendment despite being repeatedly told the Senate leadership stance was a “no” vote. He eventually switched his vote to “no.”

There had been speculation that Cochran would not run for re-election in 2008 and again in 2014, but he always returned to the fray.

His last political race was a contentious one, with Tea Party adherents running conservative state Senator Chris McDaniel in a Republican nominating election. McDaniel’s supporters accused Cochran of having an affair with longtime aide Kay Webber, but the Cochran campaign dismissed the allegation as “silly gossip.”

Rose Cochran died in December 2014 and Cochran, then 77, married Webber in May 2015.

McDaniel had drawn more votes than Cochran in the primary election but with establishment Republicans, minority voters, big-money donors and even some Democrats such as liberal former New York Mayor Michael Bloomberg rallying around him, Cochran defeated McDaniel by two percentage points in a runoff. He then easily beat a Democratic opponent in the general election to win his seventh Senate term.

During the primary campaign, a McDaniel-supporting blogger shot cellphone video of Cochran’s wife in her nursing home bed and it was posted online. The blogger was sentenced to five years in prison for conspiracy while two other men pleaded guilty and received no jail time.

Cochran, who sometimes played classical music on the baby grand piano he kept in his Senate office, was known as “Gentleman Thad” because of his mannered, genial demeanor.

“From the beginning of his career he rejected the invective of Southern demagoguery, a specialty that so many of his contemporaries were practicing when he was first elected to Congress,” journalist Curtis Wilkie, a longtime Cochran friend, wrote in Politico in 2014.

Cochran, the son of educators, was born in Pontotoc, Mississippi, on Dec. 7, 1937, and graduated from the University of Mississippi, where he was a cheerleader, in 1959. After serving in the Navy, he earned a law degree from the school and practiced for several years.