January is the cruelest month for a White House staff, numb as it watches the end of a presidency. Every day brings a last. The last Christmas, the last walk on an iced terrace, the last touch of power.

Outside the White House gates are the rows of Ronald Reagan's inaugural bleachers, surrounding the mansion like an army its captives. The inaugural viewing stand is there, too; as it went up, plank by raw plank, some inside called it the scaffold.

The phones are calm, the walls stuck with bare nails. Boxes line the hallways, full of memories unearthed from the back of desk drawers. By noon Tuesday, all the characters will be gone from the set.

Three glimpses from inside: The Press Aide

"I used to run down the halls to get to a meeting," says Paul Costello, assistant press secretary to Rosalynn Carter, "but now I've just been taking my time and enjoying the ambiance of the White House. You come to realize that it's going to be over . . .

"This transition period is like being on the plank for two months. You're kind of stepping up an inch at a time. Or it's like walking to a guillotine, 14 miles away. It's long, it's slow, and it's painful . . . Christ. When are they going to chop my head off?"

Costello's office in the East Wing is lined with mementos of his travels with the Carters: pictures from Nigeria, Spain and Paris, a mask from Liberia, a plate from Egypt. "I haven't taken these down," he says, "because I couldn't come here very day and stare at a blank wall."

The walls are soft yellow, the plants healthy in a small office that is elegant, comfortable and historical. Hopelessly heady, too, for a 28-year-old Chicagoan who did advance work for Walter Mondale's vice-presidential campaign, then joined Rosalynn Carter's staff in July 1977.

"This place was my whole life," he says. "It was seven days a week, it was waking up one morning and being told we're going to Thailand tomorrow to visit the Cambodian refugee camps, or to be told you need to be packed by 6 o'clock this evening to fly to Israel . . . "

He is tall, dark with a sprinkling of gray, the likable guy who gave good parties. And as of Tuesday at 12:01 p.m.: unemployed. He has tried out to be writer on "Saturday Night Live," interviewed for a job as a press secretary on the Hill, and worried as much as he has unabashedly promoted himself.

"Will you let me put my jacket on?" he laughs to the photographer taking his picture. "I'll look more employable."

Later, he says: "It's very easy to work in the White House and assume that people are going to search you out and break down your doors, and that the whole world is open. The whole world is open, but you've got to take the responsibility to let people know that you're talented, that you're creative.

He plays with the push buttons on his phone, smoking nonstop. In an hour, his mood runs from agressive optimism to sad reflection.

"Hey," he says softly, reflecting, "the Carter presidency came to an end. And so did a period of my life." The Speechwriter

Achsah Nesmith looks hauntingly like Rosalyn Carter, only younger. She has wide brown eyes, a milky skin, a voice that travels from deep whisper to husky accent and back. At 41, she seems to come from a Gothic novel, transplanted into the old Executive Office Building's dark midwinter silence.

That silence is broken as she talks of Jimmy Carter, the man she met when he was a candidate for Georgia governor in 1965 and who, as a defeated president in 1980, delivered the concession speech she wrote midafternoon on Election Day.

When Carter had finished with it at the Sheraton Washington, she came back to her office. A copy of the speech was still there, staring at her as she opened the door. "It was sort of like finding a ghost waiting on you," she says.

The next day, she stayed home and planted bulbs."It seemed like the only thing I could think of that would have any lasting promise," she says.

Now she won't come into her office from the Pennsylvania Avenue side. The bleachers. "I don't go that way if I can help it," she explains. "They're so ugly. It's like building a football stadium in the middle of the street."

Born and raised in Atlanta, she was a reporter covering politics for the Atlanta Constitution when she met Carter. They became friends, and after the 1976 election, Jody Powell called her up and asked if she'd like to work for the president. So she came with her husband, Jeff, to Washington.

They've been to the Carters' house in Plains, and Carter has had her in for a private lunch. Her January hurt seems more a hurt for him. "Sometimes," she says, "watching him say goodbye to people . . ." She trails off into a whisper.

Her office has high ceilings. Boxes are piled everywhere. It's drafty, cluttered and cold. Something rattles near the window.

"Sometimes," she sighs, "I feel like I just want to walk out and leave everything." The Congressional Assistant

"I wish I were out of town right now," says Valerie Pinson. "I wish I had decided to leave now instead of after the inaugural, because it's going to be very unpleasant."

Pinson, a congressional liaison assistant, will be at home packing for a vacation when the inaugural events are booming on Tuesday. She says she can't watch any of them, even on television.

"I think the thing that all of us have learned is that when you lose, everything stops," she says. "No longer is the White House the focal point. I don't think that any one of us realized that it was so final. I figured at least, come November or mid-December, that the president would still get substantial amounts of coverage, or at least be written about once in a while. I mean, I'm not sure we would have even seen Jimmy Carter's name in print if he hadn't broken his collar bone."

Pinson is 50, an attractive, gregarious woman from New York who started two decades ago as a Capitol Hill secretary and moved rapidly up to well-connected lobbyist. In 1976 she joined Carter's transition team, and in 1977, began working for his congressional liaison, Frank Moore. She is divorced, has a daughter in law school and a Northeast house with a mortgage. She's hunting, but hasn't found a job.

"That has plagued me," she says, simply. "I haven't looked for a job in 20 years."

Her office in the old EOB is piled with papers, books and signed photographs of her with the president. The room is dark, lit by a single lamp near the couch where she sits. Her window view is of the Washington Monument and a sweeping magnolia tree. "Oh," she says, "you should see it in the spring."

She has a story to tell. "A funny story," she explains. "I can remember this time four years ago, when we came in. I had stacks of invitations. I mean, I couldn't go through them fast enough. Well, this time, at the end of November, early December, I got this beautifully engraved invitation, which was the only invitation I have even seen in about three or four weeks. It says "The Honorable Valerie F. Pinson, special assistant, blah, blah, blah.'

"And I said, 'Who could be sending me an invitation? Is somebody really inviting me to something?'

"It was an invitation," she says, slowly, for effect, "to view the showing of the new furniture in the Mazza Gallerie. I mean that, to me, is a token example of how final defeat is. You are just left out of everything! I said, 'Can you believe this?' It's just incredible. It really is!

"And I can handle it," she says, more quietly. "It's just that it's so final."