That view of Mandela arose in the 1970s and 1980s during the Cold War because of Mandela's membership in the banned South African Communist Party and his advocacy of armed struggle to end the institutionalized discrimination and violence against South Africa's black majority by the white minority regime.
His organization, the African National Congress, and its armed wing received years of material and political support from the former Soviet Union, Cuba's Fidel Castro and the late Libyan dictator Moammar Gadhafi, both of whom Mandela never stopped lauding. The Cuban exile community in Miami was especially incensed by his praise of Castro.
Concerned that communism could triumph as post-colonial conflicts raged in a region abounding in strategic minerals and Western corporate investments, President Ronald Reagan swung U.S. policy from opposition to support of South Africa's white rulers soon after his 1980 election.
"Can we abandon a country that has stood by us in every war we've fought, a country that is strategically essential to the free world?" Reagan asked in a 1981 CBS News interview.
The Reagan administration invited senior South African security officials to the United States, violating a U.N. arms embargo, and the United States vetoed a U.N. Security Council resolution that would have imposed economic sanctions on Pretoria.
Reagan also had Mandela placed on the U.S. international terrorist list, where the anti-apartheid leader remained until 2008.
The moves were part of a policy known as "constructive engagement," which held that there were moderates in the South African government who understood that apartheid couldn't last and who had to be encouraged to promote reforms and reach out to the ANC.
"The issue was what diplomatic tools did you use to try to encourage the kind of evolutionary change that everybody hoped for, which is eventually what happened," said Chester Crocker, a former assistant secretary of state and the architect of the policy.
Crocker, now the James R. Schlesinger professor of strategic studies at Georgetown University's Walsh School of Foreign Service in Washington, defends the approach, saying that it gave the United States the influence it needed to persuade South Africa in 1988 to end its occupation of Namibia and to help negotiate an end to Cuban and South African military intervention in a grinding civil war in Angola.
"What we were doing was trying to end the regional wars in southern Africa, and that was a priority that was shared by the neighboring countries of South Africa," said Crocker. The Namibia and Angola settlements, he said, "set the scene" for the negotiations that ended apartheid in South Africa.
Many experts, however, charge that the policy was a major failure. Instead of moderating and instituting meaningful reforms, the white regime intensified its bloody repression of its opponents, they say.
Reagan found himself confronting growing domestic opposition to his policy, especially on university campuses, where student anti-apartheid protesters were at the forefront of a nationwide drive to end U.S. investments in South Africa.
Opposition to Reagan's approach received a major boost in 1984, when the South African anti-apartheid campaigner, Anglican Bishop Desmond Tutu, visited Washington soon after winning the Nobel Peace Prize.
In a speech on Capitol Hill, Tutu denounced constructive engagement as "an abomination," and he said that Reagan's close ties to the Pretoria regime were "immoral, evil and totally un-Christian."
Even so, Reagan decided in 1985 to veto congressional legislation to impose strict economic sanctions on South Africa, calling the measure "immoral" and "repugnant."
He found support among fellow conservatives, including former Vice President Dick Cheney, who was representing Wyoming in the House of Representatives. Four current Republican House members - Reps. Joe Barton of Texas, Howard Coble of North Carolina, Ralph Hall of Texas and Hal Rogers of Kentucky - also voted against the bill, which had passed the Senate. Hall was a Democrat at the time.
Cheney voted the following year against a congressional resolution calling for freedom for Mandela, then in his 23rd year of a 27-year prison term.
Reagan's veto, however, was overturned as other members of his Republican Party embraced the divestiture movement to isolate white-ruled South Africa and end apartheid. The votes marked the first time that the legislative branch overrode an executive branch foreign policy decision.
In a brief statement on its website, the Ronald Reagan Presidential Foundation and Library said that it was "saddened" by Mandela's death and that Reagan had "called for his release on numerous occasions." There was no mention of his veto decision.
Princeton Lyman, a veteran U.S. diplomat who served as U.S. ambassador to South Africa as Mandela helped steer the transition to democracy after his 1990 release from prison, recalled that the Reagan administration was split over the sanctions bill.
Patrick Buchanan, the conservative former presidential adviser, counseled in favor of the veto; Secretary of State George Shultz and Crocker urged against it, said Lyman, now a top official at the U.S. Institute for Peace, a congressionally funded think tank in Washington.
Shultz and Crocker "saw the writing on the wall," he said, adding that Shultz used the override to win approval for the opening of official contacts between the United States and the ANC through the ANC's headquarters-in-exile in Lusaka, Zambia.
Labeling Mandela a terrorist is a misnomer, Lyman said, because he didn't see violence as means of seizing power. Nor did he pursue it wantonly like al-Qaida or other terrorist groups, but he used it as a way of forcing the white minority rulers to the negotiating table.
"You have to look very carefully at what he felt about the armed struggle," Lyman explained. "He never believed the armed struggle was the answer to the end of apartheid. It was one way to pressure a government that wasn't moving at all."
"The ANC tried very hard not to have civilian casualties," he continued, saying that most of the bombings that the group staged took place at night against infrastructure.
Mandela's praise for Castro and other leaders, Lyman said, was driven by the gratitude that he felt for their unstinting support of the anti-apartheid movement, and he avoided passing judgment on their own authoritarian rule.
"He would say, 'These were people who were helping me when you weren't helping me,' " Lyman recalled. "He was very upfront about it."