The Iran-Contra affair exploded 20 years ago Saturday, a scandal that crippled the last two years of Ronald Reagan's presidency and temporarily damaged the career prospects of Robert Gates, President Bush's nominee to replace Defense Secretary Donald H. Rumsfeld.

On Nov. 25, 1986, Attorney General Edwin Meese announced the diversion of millions of dollars in proceeds from the Reagan administration's secret arms sales to Iran to Central America, where the money was used to help bankroll a war secretly run out of the White House. At the time, Congress had cut off military aid to the rebel force known as the Contras fighting the communist government of Nicaragua.

The National Security Archive, a private group, is posting on its Internet site some of the hundreds of thousands of government documents it has collected on the scandal, including some about Gates. His nomination to become CIA director was derailed in 1987, but Gates stayed on in government, survived the political bloodletting, was renominated by President George H.W. Bush four years later and confirmed by the Senate.

Now Senate Democrats are expected to gauge Gates' willingness to change the administration's war policies, but they probably won't stand in his way to becoming the next defense secretary.

Thirty-one Democrats voted against him in 1991, in part because some felt he had turned a blind eye to the diversion of funds to the Contras. Gates says he first heard information about the diversion nearly two months before it was disclosed to the public, and a CIA official said he first told Gates about it even earlier.

Iran-Contra Independent Counsel Lawrence Walsh investigated Gates but brought no criminal charges, concluding that Gates' statements to investigators "often seemed scripted and less than candid."

One of the central figures in the Iran-Contra affair, retired Air Force Gen. Dick Secord, said Friday that critics "have beat this dead Iran-Contra horse far too much by trying to involve Gates, which is a laugh."

Secord was recruited by CIA Director William Casey to run the secret resupply network to the rebels along with National Security Council aide Oliver North. He said Gates "was not a player and, since I was the chief of operations, I guess I would have known if he was a player."

Records Detail Role in Nicaragua

According to the records, Gates in 1984 as the CIA's No. 2 official advocated U.S. airstrikes against Nicaragua's pro-Cuban government to reverse what he described as an ineffective U.S. strategy to deal with communist advances in Central America.

Gates said the United States could no longer justify what he described as "halfhearted" attempts to contain Nicaragua's Sandinista government, according to documents released Friday by the National Security Archive, a private research group.

In a memo to CIA Director William Casey dated Dec. 14, 1984, Gates said his proposed airstrikes would be designed "to destroy a considerable portion of Nicaragua's military buildup" and be focused on tanks and helicopters.

He also recommended that the United States prevent delivery to the Sandinistas of such weapons in the future. The administration, he said, should make clear that a U.S. invasion of the country was not contemplated.

The target of Gates' anxieties was Nicaragua's leftist president, Daniel Ortega.

Gates' nomination to succeed Defense Secretary Donald H. Rumsfeld was announced just days after Ortega capped off a surprise political comeback by winning election as Nicaraguan president after three previous bids were rejected by the voters.

Ortega has recast himself as a moderate, assuring Nicaraguans that his Marxist-Leninist days are over.

Gates saw a calamitous situation in Central America in December 1984. Congress had ordered a halt to U.S. support for the Contra rebels, leaving Ortega free, as Gates saw it, to establish Nicaragua as a "permanent and well-armed" ally of the Soviet Union and Cuba.

He said the United States should acknowledge that the existence of a Marxist-Leninist regime in Nicaragua closely allied to Moscow and Havana "is unacceptable to the United States and that the United States will do everything in its power short of invasion to put that regime out."

In addition to airstrikes, he recommended withdrawal of U.S. recognition of the Nicaraguan government and recognition of a Nicaraguan government in exile that would be entitled to U.S. military support.

Economic sanctions should be considered, "perhaps even including a quarantine," Gates wrote.

His proposals were never adopted, but the administration attempted to circumvent the Contra aid ban by secretly funneling money to the rebels that had been obtained through arms sales to Iran. Democrats say they will question Gates during his Senate confirmation about his knowledge of the Iran-Contra scandal, which erupted two years after he sent his memo to Casey.

Gates' grim prediction in the memo of disaster in Central America did not come to pass. Congress renewed aid to the Contras in 1986. In February 1990, Nicaraguans dealt a blow to the Soviet Union and Cuba by voting Ortega out of office. And within two years, the Soviet Union had disappeared.