In “Second Chance: Three Presidents and the Crisis of American Superpower,” published in 2007, he assessed the consequences of that war and criticized the successive administrations of George Bush, Bill Clinton and George W. Bush for failing to take advantage of the possibilities for American leadership from the time the Berlin Wall came down in 1989. He considered George W. Bush’s record, especially, “catastrophic.” And in the 2008 presidential campaign, he wholeheartedly supported Barack Obama.

Four years later, he once again assessed the United States’ global standing in “Strategic Vision: America and the Crisis of Global Power.” Here he argued that continued American strength abroad was vital to global stability, but that it would depend on the country’s ability to foster “social consensus and democratic stability” at home.

Essential to those goals, he wrote, would be a narrowing of the yawning income gap between the wealthiest and the rest, a restructuring of the financial system so that it no longer mainly benefited “greedy Wall Street speculators” and a meaningful response to climate change.

A United States in decline, he said — one “unwilling or unable to protect states it once considered, for national interest and/or doctrinal reasons, worthy of its engagement” — could lead to a “protracted phase of rather inconclusive and somewhat chaotic realignments of both global and regional power, with no grand winners and many more losers.”

Mr. Brzezinski, who had homes in Washington and Northeast Harbor, Me., was married to the Czech-American sculptor Emilie Benes, with whom he had two children in addition to Ms. Brzezinski: Mark Brzezinski, a lawyer and former ambassador to Sweden under President Barack Obama, and Ian Brzezinski, whose career has included serving as a deputy assistant secretary of defense. All survive him. He is also survived by a brother, Lech, and five grandchildren.

Into his 80s Mr. Brzezinski was still fully active as a teacher, author and consultant: a professor of foreign policy at Johns Hopkins University’s School of Advanced International Studies, a scholar at the Center for Strategic and International Studies, and a frequent expert commentator on PBS and ABC News.

He was, in short, a man who could be counted on to have strong opinions, and a boundless eagerness to share them. Once, in 1994, he even put forward a sort of disarmament program to solve the problem of breaking ties in the final game of the soccer World Cup.

“In the event of a tie,” he wrote to the sports editor of The Times, “the game should be resumed as a sudden-death overtime, but played with only nine players on each side, with each team compelled to remove two of its defensive players. That change increases the probability of a score and places more emphasis on offensive play. If after 10 minutes of play there is still no score, the game continues with four defenders removed from each team.”