9:21 a.m. -- The briefcase emerges first, then a fold of green dress. The woman wearing it comes into full view, slipping through the limousine door and up the steps almost before her companion has left the back seat.

Inside the plane, she drops the briefcase at her seat before continuing along the aisle. At the doorway separating her compartment from a larger one at the rear, she pauses to scan the interior.Not the faces. Without speaking, she turns and returns to her seat.

She puts on reading glasses. From the briefcase come papers. Instantly the table covered with orange cloth is transformed into a desk. She sits with her back to the cockpit and appears engrossed in what she reads. Around her there is a bustle of people greeting each other, shaking hands, finding seats. She is not distracted.

The engines start up and the DC-9 known on this trip as Executive One begins to taxi. And just as it says on the memeographed schedule her staff has handed out, it is:

9:25 am EDT THE FIRST LADY DEPARTS ANDREWS AFB ENROUTE ST. PETERSBURG, FLORIDA.

The campaign hasn't yet heated up to the point where if-this-is-Thursday-it-must-be-Florida: technically this isn't the campaign. Technically, Jimmy Carter isn't a candidate, so technically Rosalynn Carter isn't the candidate's wife.

Once those technicalities are acknowledged, it is that slow-motion moment before the first hurrah peculiar to politics: a time of straw men and straw votes, fingers in the wind and fingers on the pulse, polls and pols and mounting tensions as sides get ready to square off for the biggest brass ring of all.

In fact, it happens to be Thursday, and also Florida, and Rosalynn Carter is making her second foray there in that many weeks. The last time, she raised a quarter of a million dollars; this time the Carter-Mondale Presidential Committee is emphasizing her presence. She will remind Florida Democrats through two receptions, a fund-raiser, three television appearances, two newspaper interviews and three press conferences that Jimmy Carter wants their votes at party caucuses on Oct. 13, when they elect delegates to the party convention in November. Nobody knows better than Rosalynn Carter that the caucuses will be the first test of strength between Carter and the supporters of Sen. Edward M. Kennedy (D-Mass.). And in her one-day jet-age blitz of four Gulf Coast Florida communities, she all but peels off the velvet gauntlet to reveal something of the style and role she is carving for herself in her campaign to keep Jimmy in the White House.

9:50 a.m. -- Air Force enlisted men serve 18 ham-cheese-fruit salad brunches to five Secret Service agents and 13 reporters, photographers and television technicians. For the press, it's $3 each, cash-and-carry. Veteran photographers from other Carter trips talk about "25-30-40 foot throws." These have nothing to do with shot-putting or ring-tossing, it turns out. These are the distances the White House advance team warns photographers they will have to keep from Mrs. Carter at scheduled stops. The Secret Service agents, who keep to themselves, can be expected to help.

10:25 -- Rosalynn Carter, seen through the uncurtained doorways nibbles her bruch (her $3 meal is paid for by the Carter-Mondale committee) but seldom looks up from the day's four speeches that she will deliver or the briefing papers on the day's events. She is primed to discuss Jimmy Carter's "achievements" of the past week -- passage of a bill to establish a Department of Education and "progress" toward hospital cost containment. But there will be no public reference to his speech on Soviet troops in Cuba, which started off his week. Nor will anybody ask her about it.

11:31 a.m. -- She has touched up her lipstick, put on her contact lenses, practiced her speech aloud in the privacy of the lavatory, and as the plane comes to a halt in the steamy 85-degree St. Petersburg heat, Rosalynn Carter is ready. A small band of greeters is on the tarmac, a larger contingent of local press behind the wire fence. There are questions about the upcoming caucuses ("very important"); when Carter will announce ("soon"); whether she agrees with the Carter-Mondale committee's protest to the Federal Election Commission about fund-raising efforts for Kennedy. Then there is a request for further explanation.

"I don't think it needs any explanation," she says. She is annoyed, and there is an edge to her words. "A candidate or a non-candidate should be treated the same. I thought the purpose of the law is to keep candidates from being obligated to large contributors. I'm surprised that the other, uh, forces would accept these large contributions in the first place."

Later, much later, she is asked why she never once during the day mentioned Kennedy's name.

"He's not a candidate," she says.

Noon -- There are 200 in the dark, musty hotel ballroom that can hold three times that number. The microphone is not functioning properly; Rosalynn Carter's throat is dry and scratchy. She delivers what those traveling with her soon will recognize as her all-purpose speech of the day. "Leadership" and Jimmy's "love" are constant themes.

"Jimmy told me to tell you all hello and that he cares for you."

And is the feeling mutual?

"I'm not sure yet. Who is?" whispers Edith Jewett of St. Petersburg, a registered Democrat in Pinellas County, regarded by Carter-Mondale people as Carter country.

"Her personal messages come across very well," says Wanda McGuire. "What people are looking for is whether we'll get our problems solved."

Pat McElroy, chairman of the Pinellas County Democratic Party, who has ridden in from the airport with Mrs. Carter, watches from the sidelines. He said he told her in the car she would be pleased with the outcome of the Oct. 13 caucus. The county organization has already elected 25 percent of the delegates. They are Carter people.

"It's a good county for Carter," Jay Hakes, who is running the Florida campaign, tells reporters later. "In '76 we lost, 51 to 49 percent, to Ford; for a Democrat in Pinellas that's very good."

12:43 p.m. -- "Please call me Rosalynn," she has told her WTVT-TV interviewer, who proceeds to invite her to share some "personal tidbits" with listeners. She gives no indication on camera that the questions may not have been quite what she expected:

How would she go about going public with problems she might try to hide? ("I don't have things to hide, but I suppose the time to make a decision of whether to go public is when you decided to do something about that problem.")

What were some of Jimmy's personal little habits? ("I don't know that he has problems I would like to tell you about.")

Does he leave his socks on the floor or a mess in the kitchen? ("He doesn't leave a mess; we have good help in the kitchen")

2:44 p.m. -- "I don't think there's going to be any problem for Jimmy," says Pat Carter, the wife of Jimmy's second cousin, who lives in Florida and who has come to Clearwater to see Rosalynn preside at the 35th-anniversary celebration of the Pinellas County Mental Health Center.

"You don't want to predict something," she continues, standing near the Clearwater Tornado Band, "but I can't believe that the people who say so many good things about Jimmy don't mean it."

3:40 p.m. -- Executive One is airborne again, this time for a 30-minute flight to Ft. Myers. Photographers are comparing this trip with the one two weeks earlier, a more productive one -- visually, at least, with bands and rallies and colorful ceremonials.

Rosalynn Carter, seated at her "desk," reads her speech cards.

4:30 p.m. -- "Our president is a strong, courageous, deliberative president because he has a strong, courageous, deliberative partner," State Rep. Franklin Mann says to several hundred Democratic regulars packed into the Sheraton Inn ballroom at Ft. Myers.

There are bunting and hot TV lights and sweaty bodies and the naked excitement of grassroots politics. Rosalynn Carter may sense it, for her basic speech starts to come alive.

"Now," she says, her voice rising, "now is the time of supporting an incumbent president and be about the job of solving our problems together."

"I think," Herschel Pollard Sr., of Benita Springs, says later, "that she's a co-president. She stands up and says what she thinks."

6:20 p.m. -- "Listen here," says Mary Cameron, 81, above the din of the 23rd annual Florida Democratic Women's Club reception for Mrs. Carter at the posh Beach Club Hotel in Naples. "I'm from Boston, I know the Kennedys . . . If Ted Kennedy is so wonderful, why isn't he doing more in backing up Jimmy Carter in the things Carter wants and the people want?"

If there ever was conservative Republican country, this is it; Republican-stronghold Naples is, hands-down the highest per-capita-income city in the state. But the Democratic women assembled here are transient, coming from 55 clubs around Florida. Some are pro-Carter, some pro-Kennedy, making this forum unique among those Rosalynn Carter has addressed today.

"You are our friends, we need you," she tells these women in an implicit invitation to repeat the support they gave as a group four years ago. Some, like Mary Cameron, are ready to give it. Others, like Helen Citran, Irma Rocklin and Helen Taussig, are pulling for Kennedy.

Dorothy Bush is there but refrains from making any endorsements. "You know how it is," she says. As secretary of the Democratic National Committee, she will call the roll at the party convention next month. She will ride with Rosalynn Carter in the motorcade later to the day's only fundraiser, a $250-a-couple reception.

Motorcade companions have been known to provide local political intelligence. Rep. Mann says he told Mrs. Carter in their four-minute ride from the airport to Ft. Myers that although he thinks the majority of Democrats in Lee County are for Carter, "the trouble is getting them out to vote. It didn't come as a shock to her."

7:25 p.m. -- A full moon hangs in the sky between palm trees standing sentinel around Donald and Darleen Stonebruner's $2 million pseudo-Spanish villa overlooking the Gulf of Mexico. Nobody professes to know exactly how much has been taken in from ticket sales -- maybe $25,000, maybe $10,000. But Rosalynn Carter is fired up by Stonebruner's glowing introduction of her. Though she had not planned to speak, she gets out her note cards to tell the well-heeled, well-dressed crowd that a new Congressional Quarterly study shows that Jimmy's doing better on Capitol Hill than previously though.

"When I heard all this talk about Jimmy's accomplishments, I just had to talk," she says.

8:30 p.m. -- She is standing in the aisle of Washington-bound Executive One, talking to reporters. The green dress is unwrinkled, looking as fresh as it did 11 hours earlier. She has worn it many times, she says, adding that "if you're really sweating you don't lean back."

There are other questions:

On Carter's Cuba speech ("I told him some things he ought to do, but I didn't advise him on political things. If I can understand what he says, I think anybody can").

On that morning's Jack Anderson column calling her "co-president" ("I think it's very exaggerated. I don't tell Jimmy what to do. I like to be informed, I want to know what is going on. But I don't tell Jimmy what to do and Jack Anderson knows it').

9:30 p.m. -- She has the $4.50 Executive One chicken and rice special like everybody else. And then she leans forward and starts her thank you notes.