SHE INFLUENCES him and he influences her because she believes that any couple with a healthy marriage and a strong Christian influence does that.

"Supportive, at least, and involved in his original thoughts," says Dee Jepsen of the role she plays in helping Sen. Roger Jepsen (R-Iowa) form his legislative stands and policy positions. "Anybody who knows my husband knows he's a very strong-minded man. But he also respects my opinion and he listens, as I think most good husbands should."

Yet, in a town where political wives have had considerable influence through the years, even Dee Jepsen's counsel, rooted in what she calls Judeo-Christian values, seems unique.

Through prayer and biblicalstudy, for example, and because she is the other half of what Jepsen calls "the team," she has been able to help develop her husband's pro-Israeli policy on the Middle East, reevaluate his stand on AWACs and revise the Family Protection Act, which he reintroduced last June.

"I was the hired man you sent to Washington," Jepsen likes to tell Iowa constituents, "but you got two for the price of one.

In fact, back in 1978 when Jepsen first told her he had decided to try for the Senate, Dee Jepsen had not exactly been supportive. Still painful were unhappy memories of Roger Jepsen's earlier political career that had had a meteoric rise, starting four years after their marriage with his election in 1962 as Scott County supervisor, continuing in the Iowa state senate from 1966-68 and ending in 1973 after two terms as lieutenant governor.

"He often said he didn't think the state would start in the morning if he didn't get up," remembers his wife, a young divorce'e supporting one child when she met Jepsen, an insurance salesman, in a restaurant where she worked as a waitress. ("He ordered a steak, then sent it back. He's been doing that ever since," jokes the former Dee Ann Delaney, who had been reared on a farm in Maquoketa, Iowa, and educated in a one-room school.)

Dee Jepsen says her husband was "young" (40) to be the No. 2 man in the state, with what she calls "all the human frailties of one who had no solid perspective of our value system, our principles, the whole foundation we base our lives on."

The hazards of public life being what they are, she says "you're over-stimulated all the time, stuff is coming at you all the time. There are those who admire you and hold you up and praise you no matter what you do and that's not very healthy. Then there are whose who criticize and attack you no matter what you do and that's hard to take."

Jepsen's young family of six children (her child, his four by a previous marriage and a son of their own) "once the center of his life," in time became no longer quite as important, she says.

"It was a difficult time for me . . . in looking back I'm very grateful for that because God used...people and circumstances to bring me to a point where I finally said I don't understand anything about this personal relationship, but I know I can't handle my life alone. And I asked Christ to come into my life at that point," she says.

Things didn't get better immediately. In fact, she adds, there were a number of years when things got worse.

"I prayed for Roger to come to this depth of commitment. He had been a social Christian all his life -- he was the one who taught Sunday school, not me," she says. "But this personal relationship with Jesus Christ was something he didn't have either."

Nor did he understand it, she says, though he could see it was doing "good things" in her. "He saw me sometimes being understanding and lovable in a situation that didn't call for that. He just kind of watched me . . . I sure wasn't perfect, not by a long shot."

Then, at a particularly difficult time in their lives, "for a variety of reasons, including our relationship," she says Jepsen, too, committed his life to Christ.

And that might have been that, but in 1978 Jepsen told her he was thinking about running for the Senate. Appalled at first -- "I could do nothing but cry" -- she says she finally told the Lord she would do anything He wanted her to do. She and Jepsen prayed together and out of it came their agreement to campaign as a team. If he won, they would come to Washington as a team where she would work in his office full-time.

At 47, and in little more than three years since she and Roger Jepsen came from behind to defeat incumbent Democrat John Culver, Dee Jepsen is a political force in her own right.

Working as an unsalaried volunteer, she shares a cubicle just outside her husband's office with his administrative assistant. She also shares a secretary, a press aide and a legislative assistant on Jepsen's 25-member staff.

Her day starts and ends when Jepsen's does since they commute together from their Alexandria condominium. Her schedule augments his as she sees visitors he doesn't have time to see, Iowa constituents and other callers sharing her interests "in family and human issues." Through her, Dee Jepsen says, they "relay" things to him.

To Jepsen's staff -- "like family," she says -- she is "mother confessor." She's been involved in hiring some of them ("yes, sure, I have a little input in that area"), helped them research and draft legislation and develop policy positions.

"A senator's staff is not supposed to run him," she says, "just to supplement him, provide him with information. He doesn't always agree with their suggestions. Sometimes I have a suggestion and I'm overruled, too."

And sometimes she isn't.

"I might say, as I did today about something I was interested in, 'I don't know why this approach was excluded but it seems to me it would work better like this,'" she said in a recent interview which took place in Jepsen's office.

"He said, 'Well, I don't know either and I think that's probably true and I'm going to inquire.' "

If Jepsen calls her the other half of "the team," an aide calls her the senator's "alter ego."

"They think alike and depend upon each other," says the aide. "They believe that as a couple, and a family, they come before anything else."

Dee Jepsen says that her husband doesn't have to explain everything to her because she knows what he's doing. "I read a lot of the same things. I work with the staff and I know what's happening."

She is "just another set of eyes and ears".

The Jepsens are among a growing number of congressional couples whose lives are a round of prayer breakfasts, testimonial luncheons, Bible-study coffees and Christian fellowship dinners.

She helped organize a weekly Bible study for Senate wives after the Tuesday Red Cross sessions, is active in the Congressional Wives Prayer Group and with her husband, co-founded with Rep. Jack Kemp (R-N.Y.) and his wife, Joanne, something called the Christian Rescue Effort for the Emancipation of Dissidents (CREED), which works for the relief of persecuted Soviet Christians.

From her desk in the Russell Building office, she divides her time between her husband's legislative responsibilities and helping out evangelical groups such as CREED and Strategies to Eliminate Poverty (STEP), founded about a year ago to seek ways the poor can help themselves.

Her work in STEP and her beliefs in self-help programs and voluntarism provided the basis last winter for Jepsen's letter to President Reagan urging him to consider private sector initiatives as a way to ease the strainon the federal budget.

"Big government is not only short on dollars these days," Dee Jepsen recently wrote in her monthly column to Iowans, "but it cannot reach out and extend the 'heart and hand power' that ordinary people can . . . Big government can never legislate true charity."

Last month, President Reagan named her to his newly-created President's Task Force on Private Sector Initiatives, and Dee Jepsen's growing reputation as someone to be dealt with took on added signficance. A month earlier, when announcing that he had changed his mind and decided to support the administration's proposed $8.5-billion aircraft sale to Saudi Arabia, Jepsen told how he "spent all weekend" discussing his decision with his wife.

They prayed a lot that weekend.

"I don't know if we were sitting or kneeling,"says Dee Jepsen. "We read the Bible and prayed that God would guide him in doing the right thing, and we have to trust that he did."

Deciding the right and wrong to certain issues, she says, is a matter of personal judgment and of weighing them against Judeo-Christian principles, not the result of lobbying by such well-established evangelical groups as Christian Embassy.

"They are very meticulous about not becoming political in any way. That hurts their ministry . . . These groups really do not get into politics at all," she says.

Even the Rev. Jerry Falwell of the Moral Majority, who came by Jepsen's office once but found him out, is not doing "a one-on-one, let me counsel you what to do," she says. "He's sounding a clarion call for the people of this country to look at what has happened to our value system, what has happened to the direction we're going in, and he has every right to do that."

She happens to agree with him. In her Bible studies and at testimonial luncheons with other congressional wives, they talk about the conflict between two value systems, Judeo-Christianity and "humanism."

"I think God is involved in all the affairs of men and nations. I think we're called to bring our faith into every area of life. We have a responsibility to do that, but in a spirit of love."

The danger with this movement that she sees building and surfacing around the country is that she, Roger Jepsen and evangelicals like them have to be careful not to be caught up in the zeal of their cause.

"It will be a very hollow victory if we won and we hadn't treated our brothers and sisters in this world as just and as worthwhile human beings as we are," she says.