WASHINGTON -- In one Watergate image, John Ehrlichman simply glares with every inch of clenched and jutting jaw and out-thrust lower lip.
In another, Bob Haldeman, also in the witness chair at the Senate Watergate hearings, burns in a sort of dark yet incandescent glow.
They had been President Richard M. Nixon's gatekeepers, the controllers of the president's political environment -- Mr. Haldeman as White House chief of staff, Mr. Ehrlichman his other top aide.
Fred Maroon's photographs reflect the situation of all three in the summer of 1973: under siege but fiercely defiant.
In an earlier shot, taken in far more controlled circumstances, Nixon steps between two White House columns and begins to disappear. The photograph leaves just a trailing right leg, polished black shoe and right arm in view.
Mr. Maroon looked up from his camera lens and asked about Nixon's retreat.
"He deliberately avoids us," an aide replied, giving the photographer his caption.
A quarter-century ago, Nixon submitted a one-sentence letter of resignation to Secretary of State Henry A. Kissinger and ended the 37th American presidency.
Now the Smithsonian Institution's National Museum of American History is displaying an exhibit with 145 of Mr. Maroon's black-and-white images from the Nixon era -- many of them never published nor widely viewed, all stashed in a vault for the last two decades.
A large-format book, The Nixon Years, with photographs by Mr. Maroon and text by Tom Wicker, a retired New York Times Washington bureau chief, will be published this month by Abbeville Press.
"For 25 years, I waited for the passions to cool in this American tragedy, but I ultimately realized I would not live long enough to see that happen," said Mr. Maroon, a free-lance photographer who has recorded the people and monuments of official Washington for nearly 50 years.
For Mr. Maroon, the story began early in the Nixon administration, when he was given the opportunity to photograph the presidential workday, first at the White House and then at the Committee to Re-elect the President.
He continued to work on his own after the Watergate scandal broke, covering the Senate Watergate hearings, the House impeachment hearings and finally, Nixon's resignation.
"I simply had a sense I was witnessing a pivotal moment in American history, and that I should stay with it until the conclusion," Mr. Maroon said.
In all, he shot 576 rolls of film.
When he began in 1970, Mr. Maroon witnessed "a staff in control of everything that happened." In the week before Nixon resigned in August 1974, control had been replaced by "uncertainty and apprehension."
Mr. Maroon visited Nixon's re-election committee just days after the arrest inside Democratic National Committee headquarters of a team of burglars with ties to committee officials.
"You guys will do anything to get a little publicity," Mr. Maroon cracked to Jeb Stuart Magruder, the deputy campaign director.
"It never occurred to me at the time that they had anything to do with it," Mr. Maroon said.
But the photographer gradually began to become aware of the committee's tight security, its general air of "paranoia."
"I started taking notice of things differently," Mr. Maroon wrote. "Surveillance cameras and rooms with a lot of electronic devices took on a new meaning. I thought I should photograph them and the shredding machine ... ."
When the Senate Watergate hearings opened, many of the people Mr. Maroon had met earlier at the White House and the re-election committee were summoned to testify and the photographer saw "the anguish of the situation etched on their faces."
Mr. Maroon said John Mitchell, Nixon's former campaign chairman, spotted him in the Senate Caucus Room and asked what he was doing.
"I told him I was continuing my photographic record of the Nixon era and asked whether he did not agree that what was happening was of some moment," Mr. Maroon said.
"I hope it's a fleeting moment," Mitchell replied.
Finally, it was August 1974. The Republican leaders of Congress had told Nixon he didn't have the votes to stave off impeachment. Mr. Maroon photographed the growing crowds at the White House fence; the prayer vigil for the president at the northwest gate; the man with the hand-lettered sign reading, "Don't resign."
But Nixon did resign, and in a long, rambling speech said goodbye to the White House staff.
"The speech went on for quite a long time," Mr. Maroon wrote. "It became heart-wrenching. You were glad for him when he finished because you felt such grief for the country and for what was going on inside of him."
Police arrested five men on June 17, 1972, in a break-in at the Democratic Party's national headquarters at the Watergate complex in Washington. The cover-up that followed eventually brought down the president.