Washington ? Robert Gates successfully navigated the legal and political perils of the Iran-Contra scandal. He emerged as CIA director and survived an ordeal that took a heavy toll on the first President Bush, the man perhaps most responsible for Gates’ success.

George W. Bush now has designated Gates as Donald H. Rumsfeld’s successor at the Pentagon, a job that will require the next defense secretary to find a different direction for the Iraq war, which has devastated the political fortunes of the Bush administration.

Senate Democratic leader Harry Reid of Nevada says he has questions about Gates’ involvement in Iran-Contra. Republicans plan to push the nomination through before they lose control in January.

Thomas Blanton, director of the National Security Archive, a private group that has collected hundreds of thousands of pages of documents on the scandal and published several books on it, calls Gates “the ultimate hear-no-evil see-no-evil high official during Iran-Contra.”

In a final report, Iran-Contra prosecutor Lawrence Walsh said that, “like those of many other Iran-Contra figures, the statements of Gates often seemed scripted and less than candid.”

In rebuttal, Gates said Walsh’s 1994 report was “unjustifiably disparaging, unbalanced, filled with innuendo and insinuation, and draws conclusions not supported by the evidence.”

Questions about Gates focus not on what he did in Iran-Contra, but on what he knew. CIA Director William Casey had his own parallel chain of command that excluded Gates. At the time, however, Gates was the agency’s No. 2 official.

“You would think he had to know, but was he involved? No,” former CIA officer Vincent Cannistraro said of Gates.

Former Democratic Sen. David Boren of Oklahoma, who presided over Gates’ 1991 confirmation hearings, among the longest in Senate history, said Casey shut out Gates because he was “the kind of person who wouldn’t have put up with what was going on.”

The Iran-Contra affair plagued the final two years of Ronald Reagan’s presidency and damaged the final political campaign of Bush’s father. The scandal that broke out 20 years ago this month also bruised Gates’ career, forcing him to withdraw his nomination as CIA director in 1987.

Gates soldiered on as the No. 2 official at the CIA, then went to the White House’s National Security Council. Four years later, the first President Bush nominated him for the top CIA job.

Iran-Contra was the convergence of two covert operations run by the Reagan White House – selling arms to Iran in an effort to free U.S. hostages in Lebanon and supplying arms to the Contra guerrillas fighting the leftist government of Nicaragua.

NSC aide Oliver North oversaw the Contra resupply network during a congressional ban on military aid to the rebels.

Congress was kept in the dark. The two operations were exposed when a resupply plane was shot down over Nicaragua and when a Middle East newspaper disclosed the Iran initiative.