When Democratic vice-presidential nominee Geraldine A. Ferraro was asked at a news conference last week to cite the foremost issues in the 1984 presidential election, without hesitation she declared that "they all pale by comparison" to "the war and peace issue."

That reply encapsulates what has become the central motif in Ferraro's vice-presidential candidacy, as she and running mate Walter F. Mondale paradoxically seek to portray themselves as peace candidates despite the fact that the United States is not at war.

It is a strategy engendered by the personal convictions of the two Democratic candidates as well as the political reality of running against an incumbent president riding a flush economic recovery. It also reflects a belief on the part of Ferraro's advisers that presidential elections are decided by global concerns rather than domestic pocketbook issues.

"We think the '76 election" -- in which Jimmy Carter defeated Gerald R. Ford -- "was one of the first, if not the first election in 30 years, not to be decided by foreign policy issues," said Fred Martin, Ferraro's chief speech writer who wrote Mondale's speeches for several years.

The three-term House member from Queens has become her party's most eloquent voice on the threat of nuclear war and the need for arms control. She has become particularly adroit at what might be called "Reagan bashing," a talent she demonstrated again today as she and Mondale began their fall campaign.

Democratic strategists say there has been no formal decision to give Ferraro the role of "point man" on the issue; moreover, they stress the Democrats' emphasis on a potent defense coupled with arms control overtures. And they note that Mondale endorsed a nuclear freeze in March 1982 and has mentioned arms control in virtually every speech for the past two years.

Yet when Ferraro is in full throat on the topic, she appears to pluck a deep and resonant chord within her audiences that some observers believe often eludes Mondale.

That may be because she has personalized the threat of war while recycling the Democrat's 1980 campaign depiction of Reagan as dangerously cavalier about the threat of a nuclear Armageddon.

"The question is, over the next four years, what will happen to my son, John, and your children and grandchildren?" she asked today. "Will this president, unrestrained by the need for reelection, heighten the risk of war?"

Ferraro's aides said they noticed during her first solo campaign trip to the West Coast three weeks ago that audiences seemed most deeply stirred by her pronouncements on war and peace. Since that time, the subject has occupied a preeminent place in her stump speeches and continues to elicit a visceral response from the crowds rallying around her.

"Ronald Reagan has asked, 'Are you better off than you were four years ago?' Well, the question should be, do you feel safer? And a lot of people seem to say no," said Madeleine K. Albright, a Georgetown University professor serving as Ferraro's senior foreign policy adviser.

While some Ferraro aides believe that her role as the first female vice-presidential nominee provides an intrinsic credibility when emotionally discussing nuclear war, they also are attempting to show that she is capable of rationally discussing the often arcane and masculine world of the Pentagon.

"Arms-control debates up to now have been carried on by the cognoscenti, and if you didn't understand the details of throwweight you couldn't participate intelligently," Albright added. "But one thing the freeze movement has done is stripped away some of that mystique."

Ferraro's aides acknowledge, however, that the candidate's gender also has drawbacks, including the stereotype of women as uninformed on defense issues and Ferraro's obvious lack of military experience to counter Vice President Bush's World War II record as a Navy pilot.

Mondale, Ferraro and their braintrust on defense issues are still trying to articulate the differences between Republicans and Democrats on the subject. Among the advisers to the ticket are David L. Aaron, who usually travels with Mondale and was deputy director of the National Security Council under President Jimmy Carter; Barry Carter, a Georgetown University law professor and former aide to former secretary of state Henry A. Kissinger; Walter B. Slocombe, an attorney and former deputy undersecretary of defense, and Albright.

The Democrats quickly agree with the administration's contention, made most forcefully by Defense Secretary Caspar W. Weinberger, that the Soviet military buildup is beyond the pale of what is reasonably required for self-defense.

"We're not just the peace candidates," one senior Mondale adviser said. "You're trying to develop strength as a way of deterring the Soviets from aggressive behavior. . . . Mondale has said Soviet behavior is cynical, ruthless and dangerous."

Adherence to administration policies doesn't go much further than that, however. Among the Democrats' many points of disagreement:

*Mondale would like to institutionalize summit talks with the Soviet Union, perhaps on an annual basis. On the issue of intermediate- range nuclear weapons, Mondale and Ferraro have publicly expressed interest in resurrecting the controversial "walk in the woods" proposal worked out in July 1982 by chief U.S. negotiator Paul H. Nitze and his Soviet counterpart.

*Mondale has promised to scuttle the MX missile and B1 bomber while proceeding with the next-generation Midgetman intercontinental nuclear missile and Stealth bomber. He opposes the two additional nuclear aircraft carriers endorsed by Reagan. He also would sharply cut back the amount of money now earmarked for research on Reagan's Strategic Defense Initiative, popularly known as Star Wars.

Both Mondale and Ferraro have talked about negotiating verifiable limits on anti-satellite weapons, underground nuclear testing and nuclear-tipped, sea-based cruise missiles, although some experts believe each would be difficult to verify.

*Mondale also said he will make structural changes in the Joint Chiefs of Staff, which some critics believe is currently hamstrung by interservice rivalries. In her stump speeches, Ferraro frequently ridicules Pentagon procurement practices by reciting horror stories such as $1,100 paid for a plastic stool cap. To date, she has offered no specific antidotes and at least one of the episodes cited was first detected and blocked by Pentagon officials.

Verbally cuffing the incumbents is a venerable tactic for underdog candidates and Ferraro has become increasingly strident in lambasting Reagan and Bush. But her staff hopes that she can avoid being labeled as the Democrats' hatchet woman, although that also is a typical role for vice-presidential candidates, as their running mates attempt to remain more statesmanlike.

Ferraro has carefully avoided attacking either opponent on personal grounds, while also avoiding any caricature of Reagan as a warmonger, an extremist view that one staff member calls "loony tunes." By strolling the fine line between being sharp and shrill, Ferraro hopes to avoid provoking a sympathetic backlash for her Republican opponents.

But there is another reason, according to her aides, one that Ferraro feels strongly.

"If she became a hatchet," speech writer Martin says, "she would be debasing a unique and historic candidacy."