Cambridge, Mass. — ''The next two years will be a race for our lives. If we don't turn things around by 1984 and fill the Congress up with people who are for bilateral nuclear disarmament, it will be too late.''
This is the kind of pronouncement Helen Caldicott is known for, the kind she hopes will prompt a reaction from the most apathetic listener. Although it's delivered with a lyrical Australian accent, the sting lingers on. You can almost hear her supporters yelling, ''Right on, sport!'' while her critics grumble about the way she plays on her audience's emotions.
She has been called the most effective voice against nuclear arms in the United States, and her quotable phrases resonate with a cadence timed for snappy Page 1 headlines. In New England churches and Midwestern Grange halls, in high school auditoriums and before the US Congress in Washington, she confronts her listeners with graphic descriptions of the physical consequences of nuclear war, using blackboard diagrams to explain the capabilities of MX missiles and the effects of radioactive isotopes. She wants to educate, to raise moral questions, to crack through her listeners' defenses, and make them cry if necessary to get them feeling.
''You've got to talk about feelings,'' she contends. ''And because I travel continuously, I know how the country is feeling. In the groups I speak to, people are starting to ask the questions that show they're concerned with the moral and ethical values of nuclear war. They're starting to take individual responsibility and to say, 'I myself have to change, and I have to help other people change.' ''
In much the same way that she helped to galvanize Australian public opinion against French atomic tests in the South Pacific in the early 1970s (leading to the election of a new ruling party in Australia that succeeded in having the International Court of Justice in The Hague declare a ban on nuclear atmospheric testing in that area), Dr. Caldicott today is carrying the message of bilateral disarmament from one coast of her adopted homeland to the other. Physicians for Social Responsibility, the Boston-based antinuclear coalition she heads, has grown from 10 members in 1979 to more than 30,000 today.
Membership in groups of similarly concerned professionals is also increasing, including the Union of Concerned Scientists, the Lawyers' Alliance for Nuclear Arms Control, and Educators for Social Responsibility. Last month a grass-roots drive to halt the arms race won the support of voters in eight of nine states where the issue appeared on the ballot, with an estimated 10.8 million Americans voting in favor of a bilateral and verifiable nuclear freeze, compared with 7.2 million who voted against it.
Dr. Caldicott is less interested in playing the numbers game than she is in building a groundswell of public sentiment that will lead to solutions. She's encouraged by the ''revolution in thought'' she says is taking place today.
''The enemy image is becoming anachronistic,'' she explains. ''People are learning that man can't fight anymore, or that if he does, the only weapon he can use is his larynx, which leads to conflict resolution.''
While many of her responses have a well-rehearsed rhythm, to talk with Dr. Caldicott in her quiet Cambridge office, decorated with sunny posters and freshly cut flowers, is to be reminded of the fundamental concerns that motivate her. A pediatrician who specializes in genetic damage, she has temporarily given up her medical practice to work on behalf of the antinuclear movement. She wants to make the world safer for her own three children and for her patients.
''It wasn't until I had my first baby that I knew I would die to save another human being's life,'' she recalls. ''Every day I'd wake up and the sky would be bluer than it was the day before. It was just incredible to be a mother.
''As a physician, I also know what it is to establish a doctor-patient relationship with one person and get him to start thinking so that he can make decisions about what he wants to do with his life. When I address huge audiences , I try to approach them in a clinical, loving way that is not threatening, but that gets to the issues that need to be talked about. I speak to them in terms of all the things they really love.''
What is it that Helen Caldicott really loves?
''My family is No. 1 - absolutely.''
After several rocky years in the early 1970s, when she was working more than 80 hours a week, away from her husband and children for long periods of time, angry ''for all the traditional reasons that women are angry,'' and depressed over her parents' deaths, Dr. Caldicott has emerged with a buoyancy and conviction that are practically contagious.
Her children (Philip, age 19, Penny, 18, and William, 16) taught her a lot about herself, she says. ''I learned that you have to grow up to become a good parent. I had to learn to say, 'I will give up my work for you - you are my No. 1 priority,' and be prepared to totally release the outcome.''
She also attributes her newfound inner peace to a discovery of spiritual values. ''I was a scientist and an atheist for a lot of years - you know, 'Prove it to me.' Then I learned that God is reality, life per se. I found indeed that there is something higher up because I could prove it to myself by experiment. It's being open to do the right thing - not saying, 'I and my ego will decide what I will do,' but, 'God, tell me what the right thing is to do.' And the answer is always there.''
In her talks to various church groups, Dr. Caldicott often quotes from the Bible and from Jesus. ''We're at a crossroads in time, and it's . . . imperative that we evolve spiritually,'' she says. ''We have to be sure that the people who run the world are people who are in touch with their feelings and with basic morality.''
Her first book, ''Nuclear Madness: What You Can Do!'' has become a best seller within the antinuclear movement, and she's now at work on a second. Part of it will deal with what she calls the ''positive feminine principle - the loving, nurturing, caring, protective instinct that now is coming to the fore.''
Her husband, Dr. William Caldicott, says, ''It took me a while to listen to what she was saying, but now she's become my hero. She has enormous courage and enormous intelligence, and I hope others will take the time to listen to her, too.''
And who are Helen Caldicott's heroes?
''My husband, Bill, of course, because I've seen him change from a man who was blocked emotionally to a sensitive, caring man. He didn't particularly like it when I told him it was his turn to care for the children while they were growing up, but he did it. Now he's grateful because he got to know them as he never would have otherwise.''
Dr. Caldicott's delft-blue eyes and engaging smile turn slightly pensive as she considers another name on her list of favorites.''
Bertrand Russell is one of my heroes, too, because he had absolute intellectual honesty and integrity. He would take a very strong stand, but if proved to be wrong, he would say, 'Yes, I was wrong.' I respect that, and that's what I hope I can have.''