James Schlesinger, a Republican economist who advanced rapidly to some of the highest positions of government power in the 1970s but whose abrasive leadership style led to conflicts with presidents, bureaucrats and the American public, died March 27 at a hospital in Baltimore. He was 85.

The cause was complications from pneumonia, said his daughter Ann Schlesinger. He was an Arlington, Va., resident.

Schlesinger specialized in the economics of national security, which helped propel his rise during the Cold War from academia to influential jobs in the federal government, including CIA director, secretary of defense and the nation’s first secretary of energy.

He gained a reputation as someone willing to cut jobs and implement unpopular policies with little regard for what other people thought of him. In 1969, Schlesinger joined the Nixon White House staff as deputy director of the Bureau of the Budget, where he overcame Pentagon opposition to cut $6 billion from the defense budget during the Vietnam War. Impressed, Nixon named him chairman of the Atomic Energy Commission.

After Nixon won re-election in 1972, he effectively fired CIA Director Richard Helms after the two clashed over Helms’ refusal to impede the FBI investigation into the Watergate break-in.

Nixon appointed Schlesinger to lead the intelligence agency, which the president deeply distrusted.

FIRING 10 PERCENT OF CIA

“Get rid of the clowns,” Nixon told Schlesinger, referring to the CIA’s staff. “What use are they? They’ve got 40,000 people over there reading newspapers.”

He took Nixon’s order to heart and in three months forced out 10 percent of the agency staff.

During Schlesinger’s 17-week tenure at the agency, information surfaced that the CIA had offered technical assistance for the September 1971 break-in at Daniel Ellsberg’s psychiatrist’s office.

A few years earlier, Ellsberg, a onetime defense analyst, had leaked to The New York Times a secret Pentagon history of the events leading to the Vietnam War.

Schlesinger was furious. He considered the break-in a violation of the CIA charter, which prohibits the agency from acting as a domestic secret police. He sent a memo to the CIA staff asking for information about any illegal activities the CIA had conducted since 1959. The responses revealed a history of illegal spying against Americans. The CIA would uncover nearly 700 violations of its charter.

All the while, Nixon’s Cabinet was unraveling amid the Watergate affair. Nixon nominated Schlesinger as secretary of defense to replace Elliot Richardson.

When Schlesinger became defense secretary, in 1973, the U.S. troop presence in Vietnam was in the hundreds and declining.

His primary goal was to reform U.S. nuclear strategy, which relied on the threat of massive retaliation to annihilate the Soviet Union in the event of war.

Because the Soviet Union appeared to have achieved parity and the ability to respond to any U.S. attack, Schlesinger believed the old strategy was antiquated. He sought a more flexible policy that would prevent uncontrolled escalation by using limited strikes against military and industrial installations.

His views were deeply unpopular with Congress and with U.S. allies in Europe, who thought his proposal courted a nuclear exchange and made all-out war more likely. As part of a Cabinet shake-up, he was fired by President Gerald Ford in late 1975.

Ford and Schlesinger never connected, and those around the president described Schlesinger as prone to lecturing Ford in a condescending way about military strategy.

Everything about Schlesinger seemed to annoy Ford, including Schlesinger’s disheveled attire. Ford took offense that he neither tightened his tie nor buttoned his collar before meeting with the president and often slung a leg over armchairs in the Oval Office.

“His aloof, frequently arrogant manner put me off,” Ford later told historian Walter Isaacson. “I could never be sure he was leveling with me.”

SWITCHING ALLEGIANCES

During the 1976 Republican primary, Schlesinger backed California Gov. Ronald Reagan’s challenge to Ford. After Ford won the nomination, Schlesinger switched his allegiance to the Democratic nominee, former Georgia Gov. Jimmy Carter.

Carter won and named Schlesinger his top energy policy adviser. When the Department of Energy was created in 1977, Carter appointed him secretary. Schlesinger set out to end natural gas price controls and reduce oil imports, and he argued for increased use of domestic coal and nuclear power to reduce dependency on oil.

Schlesinger’s advocacy of nuclear power roiled environmental activists, especially after the 1979 partial meltdown at the Three Mile Island nuclear power plant near Harrisburg, Pa.

Actress Jane Fonda and Gov. Jerry Brown, D-Calif., sought Schlesinger’s dismissal, and they organized a Washington rally against his nuclear policies.

Schlesinger helped draft a far-reaching energy reform bill in 1978 that ended natural gas price controls, offered a tax incentive for Americans to install solar panels on their homes and levied a tax on gas-guzzling vehicles.

It was a short-lived victory for the administration. Within months, the shah of Iran was deposed, and the subsequent Islamic regime halted oil exports to the United States. Gas prices soared, consumers panicked and drivers formed long lines at gas stations. Schlesinger sometimes seemed unsympathetic, and he blamed American driving habits for the problem.

Schlesinger became a symbol of the long gas lines that “marked the beginning of the end of the Presidency of Jimmy Carter,” wrote energy analyst Daniel Yergin in “The Prize,” his Pulitzer Prize-winning history of the American oil industry. Schlesinger left office in July 1979, part of a Cabinet reshuffling by Carter, whose poll numbers were sagging.