Ted Kennedy’s greatest contributions—affecting hundreds of millions of Americans—were on domestic issues such as health, education, labor, and civil rights. But with the exception of his opposition to the war in Iraq, he played a largely overlooked but important role in international affairs, fighting for refugees from Vietnam to Ethiopia to Iraq and crusading against political oppression in nations such as Pakistan, Chile, Northern Ireland, and South Africa.

His first venture came in 1965 when he used an obscure chairmanship, a Judiciary Subcommittee on Refugees and Escapees, to get involved in Vietnam issues. He started out as a Johnson administration cheerleader, saying the Vietcong was using phony refugees to infiltrate government areas. But the hearings he conducted soon made it clear that Washington did not know and Saigon did not care about the scope of the problem—a case he made in Look magazine after a November 1965 visit to Vietnam.

Kennedy’s best-known position on foreign affairs was his opposition—early and often—to the war in Iraq.

Over the next couple of years, he successfully pressed the administration to do more for the medical care of civilian victims of the war, especially of American artillery and bombing. He went back in 1968 thoroughly prepared, having sent four aides in advance to look at the problems and then show them to him. After that trip he called Saigon’s officials corrupt “colonialists in their own nation,” and said the United States should pull out if South Vietnam’s government did not shape up.

• Adam Clymer: Ted Kennedy, the Eulogist• Adam Clymer: Teddy's Friends Raised Millions for Memorial While never the most prominent foe of the war, Kennedy became increasingly outspoken in the next few years. In 1971, he accused President Nixon of delaying peace talks to coordinate them with his own reelection campaign. And when Congress convened in 1973, Kennedy led an effort to put the Senate’s Democratic caucus on record against any further spending on the war. He won 36 to 12. After House Democrats followed suit, Nixon was able to use their votes to persuade South Vietnam to return to the negotiating table in Paris and agree to end the war.

A refugee issue also spurred his first speech in the Senate after Robert Kennedy’s death and later a rare agreement with the Nixon administration. In September 1968, he said starvation among in Biafra, a breakaway state from Nigeria, was costing more than 7,000 lives a day while the United States government stood “paralyzed.” The Johnson administration did not react, but the Nixon administration sent a refugee coordinator and then substantial quantities of food.

But the other great famine of the Nixon years got no such attention from the administration. It occurred when Pakistan, which had the firm support of Nixon and Henry Kissinger, sought to suppress an independence movement in East Pakistan or Bangladesh, as the Bengalis called their country. After millions of refugees fled Pakistan’s army into Eastern India and Kennedy visited refugee camps and said he saw “one of the most appalling tides of human misery in modern times.” Though the administration remained resolute in support of Pakistan, even after it stupidly invaded India and was routed, it did send more food aid to the refugee camps.

Kennedy’s longest connection with any foreign issue was over Northern Ireland. It began almost casually. He was taking a walk in a London park in 1971 when a woman came up to him and demanded to know why Kennedy, an Irish-American, was silent when the British locked up Irish Catholics without trial and stood by when Protestant paramilitary groups attacked Catholics. His first reaction was a simplistic “Brits out” message, demanding that the six Northern countries be united with Catholic Ireland. But after he met with John Hume, a Social Democrat from Derry, in 1972, he was quickly convinced that was impractical, and that he should support efforts for equal treatment in Ulster.

On St. Patrick’s Day, 1977, he joined with Tip O’Neill, Pat Moynihan, and New York Gov. Hugh Carey to urge Irish-Americans to stop sending money to support the violence of the Irish Republican Army. And he persuaded the Carter administration to promise economic aid if a settlement could be reached in Northern Ireland. On subsequent St. Patrick’s Days, he would meet with leaders from all factions in Washington, urging accommodation.

In 1993, he persuaded President Clinton to appoint his sister, Jean Kennedy Smith, as ambassador to Ireland. When he visited her in Dublin the next year, she urged him to support a United States visa for the IRA’s Gerry Adams, who was banned as a terrorist. When Hume told him that Adams might now be force for peace, Kennedy agreed and, over the objections of the British and the State Department, Clinton ordered the visa to be issued. The inclusion of Adams and other IRA hard-liners proved necessary to the eventual success of peace talks in 1998.

The oppression in Chile was less arguable, and the United States’ role was clear. A 1973 military coup overthrew the popularly elected left-wing government of Salvador Allende, whom the United States worked against. Admiral Augusto Pinochet’s new regime shot hundreds of Allende’s supporters in the National Stadium, although the United States Embassy whitewashed the new regime. By 1973, Kennedy had assembled enough support in the Senate to enact a ban on all arms sales to Chile, and in 1981 secured a ban on all aid to that nation until it provided basic human rights. In 1986, he visited Chile, and despite government-run demonstrations against him, met with and encouraged opposition politicians and mothers who came with pictures of children who had been “disappeared” by the military.

In 2008, President Michelle Bachelet of Chile, herself tortured and exiled by the Pinochet regime, presented Kennedy with the Order of the Merit of Chile, saying “you were there for us when human rights were being massively and systematically violated, when crime and death was around our country. You are one of the great, good, and true friends of Chile.”

He also heartened the opposition in South Africa. He visited that country in 1985, after Archbishop Desmond Tutu persuaded him that his presence would draw attention to apartheid through the American television crews that followed him. He visited slums and resettlement areas. His trip was denounced by the South African government and by the United States ambassador, Herman Nickel. Kennedy staged an illegal protest outside Pollsmoor Prison, where Nelson Mandela was being held. He said, “Behind these walls are men that are deeply committed to the cause of freedom in this land.” Years later, Mandela said he knew Kennedy had been at the gate of the prison and that “gave us a lot of strength and hope, and the feeling that we had millions behind us both in our struggle against apartheid but in our special situation in prison.”

On his return, Kennedy led an effort to impose economic sanctions on South Africa. In 1986, Congress overrode a veto by President Reagan and enacted a ban on all new investment by Americans in South African businesses and on the importation of such products as steel, coal, ammunition, and food from South Africa. “The time for procrastination and delay is over,” Kennedy said. “Now is the time to keep the faith with Martin Luther King, Desmond Tutu, and all those who believe in a free South Africa.”

In the '70s and '80s, Kennedy made four unusual visits to the Soviet Union, going not as a committee chairman or as part of a delegation (unless you counted the relatives who sometimes went along), but as an individual senator whose brother had been president. All four trips had led to the release of families and individuals, mostly Jewish refuseniks including Natan Sharansky. The 1974 trip also led to an exit visa for the renowned cellist, Mstislav Rostropovich, to leave the USSR.

The most substantive element of his talks with Brezhnev in 1974 and 1978 and then with Mikhail Gorbachev in 1986 and 1990 was in explaining American presidents—leaders with whom he had sharp differences—to the Kremlin.

He insisted to Brezhnev that Carter was committed to nuclear disarmament despite some confusing speeches on the issue. He told Gorbachev that while he personally thought it was a bad idea, Reagan deeply believed in space-based missile, defense or “Star Wars.” Later he told Gorbachev that President George H.W. Bush was not trying to score political points when he warned the Soviet leader not to use force against breakaway Lithuania. Then, on his return to Washington, he explained to Bush Gorbachev’s own view of his problems with hard-liners who thought he was too soft on Lithuania.

Kennedy’s best-known position on foreign affairs was his opposition—early and often—to the second war in Iraq. Before the war began, he said it could “swell the ranks of al Qaeda sympathizers and trigger an escalation in terrorist acts.” And he complained, “The administration has not explicitly acknowledged, let alone explained to the American people, the immense post-war commitment that will be required to create a stable Iraq.” He chided his colleagues for surrendering the congressional power to declare war to President George W. Bush.

He kept up the criticism as the war unfolded, accusing the administration in 2003 of telling “lie after lie” while its “trumped-up reasons for going to war have collapsed.” In 2004, he said, “If Congress and the American people knew the whole truth, America would never have gone to war.” Later that year he said the administration had hopelessly mismanaged reconstruction and “failed to see the insurgency that took root last year and began to metastasize like a deadly cancer.” And in 2005 he became the first prominent officeholder to call for a timetable for withdrawal from Iraq.

Just as his leadership had cheered Chileans and Nelson Mandela, it mattered to some of his Senate colleagues. As Sen. Dick Durbin of Illinois, who served in the majority whip’s position Kennedy had once held, said in 2008, “I think what he did was to give us an historical perspective…. He had seen a lot of these votes come and go, momentous, historic votes, and the fact that he was clear and firm and didn’t waver gave us a lot of confidence that we were on the right side, even if it was the minority side.”

Kennedy put a simple stamp on his opposition. Recalling his October 10, 2002, vote, he said four years later at the Massachusetts Democratic convention in Worcester: “My vote against this misbegotten war is the best vote I have cast in the United States Senate since I was elected in 1962.”

Adam Clymer is a former chief Washington correspondent of the New York Times and author of Edward M. Kennedy: A Biography.