In grand jury sessions, including with New York Times reporter Judith Miller, Fitzgerald has pressed witnesses on what Cheney may have known about the effort to push back against ex-diplomat and Iraq war critic Joseph Wilson, including the leak of his wife's position at the CIA, Miller and others said. But Fitzgerald has focused more on the role of Cheney's top aides, including Chief of Staff I. Lewis Libby, lawyers involved in the case said.
One former CIA official told prosecutors early in the probe about efforts by Cheney's office and his allies at the National Security Council to obtain information about Wilson's trip as long as two months before Plame was unmasked in July 2003, according to a person familiar with the account.
It is not clear whether Fitzgerald plans to charge anyone inside the Bush administration with a crime. But with the case reaching a climax - administration officials are braced for possible indictments as early as this week - it is increasingly clear that Cheney and his aides have been deeply enmeshed in events surrounding he Plame affair from the outset.
It was a request by Cheney for more CIA information that, unknown to him, started a chain of events that led to Wilson's mission three years ago. His staff pressed the CIA for information about it one year later. And it was Libby who talked about Wilson's wife with at least two reporters before her identity became public, according to evidence Fitzgerald has amassed and which parties close to the case have acknowledged.
Lawyers in the case said Fitzgerald has focused extensively on whether behind-the-scenes efforts by the vice president's aides and other senior Bush aides were part of a criminal campaign to punish Wilson in part by unmasking his wife.
In a move people involved in the case read as a sign that the end is near, Fitzgerald's spokesman Monday told the Associated Press that the prosecutor planned to announce his conclusions in Washington, where the grand jury has been meeting, instead of Chicago, where the prosecutor is based. Some lawyers close to the case cited courthouse talk that Fitzgerald might announce his findings as early as Wednesday.
In the course of the investigation, Fitzgerald has been exposed to the intense, behind-the-scenes fight between Cheney's office and the CIA over prewar intelligence and the vice president's central role in compiling and then defending the intelligence used to justify the war. Miller, in a first-person account Sunday in the Times, recalled that Libby complained in a June 23, 2003, meeting in his office that the CIA was engaged in ''selective leaking'' and a ''hedging strategy'' that would make the agency look equally prescient whether or not weapons of mass destruction were found in Iraq.
The special prosecutor has personally interviewed numerous officials from the CIA, White House and State Department.
Starting in the days after the Sept. 11, 2001, terrorist attacks, the vice president was at the forefront of a White House campaign to persuade Congress and the American public that invading Iraq was central to defeating terrorists worldwide. Cheney, a longtime proponent of toppling Saddam Hussein, led the White House effort to build the case that Iraq was an imminent threat because it possessed a dangerous arsenal of weapons.
Before the war, he personally traveled to CIA headquarters for briefings, an unusual move that some critics interpreted as an effort to pressure intelligence officials into supporting his view of the evidence.
Administration officials acknowledge that Cheney was immersed in Iraq intelligence, and pressed aides repeatedly for information on weapons programs. He regularly requested follow-up information from the CIA and others when a piece of intelligence caught his eye. Wilson's trip, for example, was triggered by a question Cheney asked during a regular morning intelligence briefing. He had received a Defense Intelligence Agency report alleging Iraq had sought uranium from Niger and wanted to know what else the CIA may have known. Cheney's office was not told ahead of time about the Wilson mission to investigate the claim.
In the Bush White House, Cheney typically has operated secretly, relying on advice from a tight circle of longtime advisers, including Libby, David Addington, his counsel, and his wife and two children, including Liz, a top State Department official.
But, a former Cheney aide, who requested anonymity, said it is ''implausible'' that Cheney himself was involved in the leaking of Plame's name because he rarely, if ever, involved himself in press strategy.