David M. Abshire, a leader among Washington decision-makers who helped found one of the capital’s most influential think tanks, served as U.S. ambassador to NATO and was tapped to lead the Reagan administration’s response to the Iran-contra controversy, died Oct. 31 at a nursing home in Alexandria, Va. He was 88.

The cause was complications from pulmonary fibrosis, said his wife, Carolyn Abshire.

Dr. Abshire was a veteran policymaker who spent much of his career leading the Center for Strategic and International Studies (CSIS), a respected institution that he helped establish in 1962. Several times he interrupted his work there to accept appointments in Republican administrations.

Among Democrats and Republicans, he was known for his commitment to building bipartisan consensus. His tact, former secretary of state Henry Kissinger once remarked, was “a truly artistic performance.”  

Dr. Abshire rose to perhaps his most prominent public roles when Ronald Reagan was elected to the White House in 1980. Dr. Abshire led the transition team’s national security group and surfaced several times as a candidate for the post of national security adviser. From 1983 to early 1987, he was the country’s representative to NATO, where, amid the tensions of the Cold War, he helped build European support for deploying cruise missiles to Western Europe.

David M. Abshire, founder of think tank and a former ambassador to NATO, in 1987. (Douglas C. Pizac/AP)

Dr. Abshire was preparing to return home from that job when Reagan began confronting questions about the administration’s role in the secret sale of weapons to Iran and the diversion of proceeds from the deal to anti-Marxist rebels in Nicaragua.

In December 1986, Reagan named Dr. Abshire special counselor to the president, with Cabinet rank. He was tasked with overseeing the White House’s response to investigations by congressional committees and by independent counsel Lawrence E. Walsh, so that the rest of the White House could continue to carry out its responsibilities.

Dr. Abshire, who held the post for three months, said he took the job on the condition that he be permitted to meet alone with the president. In news accounts, he was described as a consistent advocate for transparent responses to investigatory inquiries.

“The Administration is going to be criticized by these committees for the way the policy implementation went wrong,” he once told the New York Times. “And our purpose is not to prevent that. Our purpose is to carry out the function of getting out the information and the documents, and let the chips fall where they may.”

It was not the President’s responsibility to record what happened at meetings, Dr. Abshire said in a television interview. But, he said, the lack of a record carried secrecy too far.

“That first decision on the sale of arms,” he said, “should have been done on paper and not handled the way that it was.”

The Iran-contra investigation, which many Reagan defenders regarded as overzealous and costly, led to the conviction of several high-ranking officials. Walsh’s report unearthed “no credible evidence” that the president had broken the law but did find that he had “set the stage for the illegal activities of others.”

By pushing for transparency, Dr. Abshire “did perform an enormous service to both Reagan and the country,” Lou Cannon, a former Washington Post reporter and Ronald Reagan biographer, said in an interview. “He did the right thing, and he didn’t hesitate, and he didn’t think about the politics of it.”

David Manker Abshire was born April 11, 1926, in Chattanooga, Tenn. He graduated in 1951 from the U.S. Military Academy at West Point, N.Y., and saw combat during the Korean War, receiving the Bronze Star Medal. After the war, he received a PhD in American history from Georgetown University in 1959.

After working at a predecessor to the American Enterprise Institute, he joined retired Navy Adm. Arleigh Burke in founding CSIS. Once associated with Georgetown University, it grew into a think tank whose members include Kissinger and former national security advisers Zbigniew Brzezinski and Brent Scowcroft.

In the Nixon administration, Dr. Abshire was assistant secretary of state for congressional relations. Later, he was chairman of the U.S. Board for International Broadcasting, with oversight over Radio Free Europe and Radio Liberty.

Dr. Abshire edited or wrote several books, including “Preventing World War III: A Realistic Grand Strategy” (1988), “Saving the Reagan Presidency: Trust Is the Coin of the Realm” (2005) and “A Call to Greatness: Challenging Our Next President” (2008). In his recent work, including as a former chief executive of the Center for the Study of the Presidency and Congress, he promoted comity in politics.

Survivors include his wife of 57 years, Carolyn Sample Abshire of Alexandria; five children, the Rev. Lupton Abshire, an Episcopal minister, of Fort Collins, Colo., Anna Bowman of Kailua, Hawaii, Dr. Mary Lee Jensvold of Ellensburg, Wash., Phyllis d’Hoop of the District and Caroline Hall of Chapel Hill, N.C.; and 11 grandchildren.

During the Iran-contra controversy, Dr. Abshire offered an indication of why he supported transparent investigations. Working under President Richard Nixon, he said, he had witnessed the administration’s attempt to conceal the secret bombing of Cambodia.

“That was an example,’’ Dr. Abshire told the Times, “of how not to do it.”