Zbigniew Brzezinski, who helped break down economic barriers between the Soviet Union, China and the West as President Jimmy Carter's national security adviser has died aged 89.
His death was announced on social media on Friday night by his daughter, MSNBC host Mika Brzezinski. She called him "the most inspiring, loving and devoted father any girl could ever have".
In a statement, Mr Carter called Mr Brzezinski "a superb public servant" as well as "brilliant, dedicated and loyal".
Mr Carter had been impressed with the views of the foreign policy expert well before he won the presidency in 1977. That he immediately liked the Polish-born academic advising his campaign was a plus.
"He was inquisitive, innovative and a natural choice as my national security adviser when I became president," Mr Carter said.
"He helped me set vital foreign policy goals, was a source of stimulation for the departments of defence and state, and everyone valued his opinion. He played an essential role in all the key foreign policy events of my administration."
Earnest and ambitious, Mr Brzezinski helped Mr Carter bridge wide gaps between the rigid Egyptian and Israeli leaders, Anwar Sadat and Menachem Begin, leading to the Camp David accords in September 1978.
Three months later, US-China relations were normalised, a top priority for Mr Brzezinski.
He also had a hand in two other controversial agreements: the SALT II nuclear weapons treaty with the Soviet Union and the Panama Canal treaties ceding US control of the waterway.
"He was brilliant, dedicated and loyal," said Mr Carter, who awarded Mr Brzezinski the Presidential Medal of Freedom days before leaving office in 1981.
Born in Warsaw and educated in Canada and the US, Mr Brzezinski was an acknowledged expert in Communism when he attracted the attention of US policymakers.
In the 1960s he was an adviser to John F Kennedy, served in the Johnson administration and advised Hubert Humphrey's presidential campaign. He was the first director of the Trilateral Commission, an international discussion group, serving from 1973 to 1976.
In December 1976, Mr Carter offered him the position of national security adviser. Mr Brzezinski had not wanted to be secretary of state because he felt he could be more effective working at Mr Carter's side in the White House.
He often found himself in clashes with colleagues like Secretary of State Cyrus Vance. For the White House, the differences between Mr Vance and Mr Brzezinski became a major headache, confusing the American public about the administration's policy course and fuelling a decline in confidence that Mr Carter could keep his foreign policy team working in tandem.
The Iranian hostage crisis, which began in 1979, came to dramatise America's waning global power and influence and to symbolise the failures and frustrations of the Carter administration. Mr Brzezinski, during the early months of 1980, became convinced that negotiations to free the kidnapped Americans were going nowhere. Supported by the Pentagon, he began to push for military action.
Mr Carter was desperate to end the standoff and, despite Mr Vance's objections, agreed to a long-shot plan to rescue the hostages. The mission, dubbed Desert One, was a complete military and political humiliation and precipitated Mr Vance's resignation. Mr Carter lost his re-election bid against Ronald Reagan that November.
Mr Brzezinski went on to ruffle the feathers of Washington's power elite with his 1983 book, Power And Principle, which was hailed and reviled as a kiss-and-tell memoir.
"I have never believed in flattery or lying as a way of making it," he told The Washington Post that year. "I have made it on my own terms."
The oldest son of Polish diplomat Tadeus Brzezinski, Zbigniew was born on March 28 1928. He attended Catholic schools during the time his father was posted in France and Germany.
The family went to Montreal in 1938 when the elder Brzezinski was appointed Polish consul general. When Communists took power in Poland six years later, he retired and moved his family to a farm in the Canadian countryside.
At his new home, the young Brzezinski began learning Russian from a nearby farmer and was soon bitten by the foreign policy bug.
His climb to the top of the foreign policy community began at Canada's McGill University, where he earned degrees in economics and political science. Later at Harvard, he received a doctorate in government, a fellowship and a publishing contract - for his thesis on Soviet purges as a permanent feature of totalitarianism.
He made frequent trips to Eastern Europe and wrote several books and articles on Communism in the 1950s. Throughout his career, he would be affiliated with moderate-to-liberal groups, including the Rand Corp, the Council on Foreign Relations, Amnesty International and the NAACP.
Warning in lectures of fractures within the Communist movement, Mr Brzezinski emerged in the mid-1960s as a defender of the American presence in Vietnam. Unless the US put up an effective resistance there, he argued, Communist nations such as China would be emboldened to engage the West by fomenting trouble in politically unstable regions.
Nevertheless, he characterized himself as a "dawk", suggesting he might have had reservations about other aspects of American policy in south-east Asia.
Impressed nonetheless, the Johnson administration appointed him to the State Department's Policy Planning Council in 1966. Though he was low on the White House totem pole, the position gave Mr Brzezinski access to the highest circles of decision-making.
After Mr Carter left office, Mr Brzezinski returned to lecturing, writing and serving on commissions, boards and task forces. He took part in the long-awaited reunification of Europe as a delegate to proceedings designed to bring the former Soviet republics into the North Atlantic Treaty Organisation.
It was a triumph for the allies, he said, over a brutal secret non-aggression deal hatched during the Second World War - "the final undoing in Europe of the legacies of the Stalin-Hitler pact".
He remained engaged and opinionated, tweeting for the last time early this month: "Sophisticated US leadership is the sine qua non of a stable world order. However, we lack the former while the latter is getting worse."
As well as his daughter Mika, he is also survived by his wife, Emilie, and sons, Ian and Mark.