Some time in the last 30 days, the name of the 39th president of the United States has been changed from Jimmy Carter to Difficult Circumstances.

That fact became apparent when Walter F. Mondale appeared last Friday at the reorganization meeting of the Democratic National Committee. He managed, in the course of his remarks, to omit uttering the name of the president for whom he and all his listeners had campaigned, oh so recently.

When it came time for him to praise retiring DNC chairman John C. White, Mondale said only that his old friend and ally had been chairman under "Difficult Circumstances."

How difficult the circumstances were for the Democratic Party under Carter was starkly displayed in an independent financial audit that pro-Kennedy members of the party's executive committee insisted on having made after the election.

It showed, among other things, that the Democratic National Committee received almost $1 million less in small direct-mail contributions in 1980 than it had in 1976, when Jerry Ford was in the White House. It showed that the party spent about $800,000 more in 1980 than in 1976 in direct support of the presidential campaign, but only half as much on voter registration. It also showed that the Democratic National Committee paid out more money for Patrick Caddell's polls for the presidential campaign than it contributed to all the other Democrats running for office in 1980.

It is that sort of pattern that explains Senate Minority Leader Robert C. Byrd's caustic comment to the DNC meeting that "never again must the DNC become the adjunct of the Committee to Reelect the President."

The implicit comparison to Richard Nixon's "CREEP" did not escape anyone -- and that is about as cruel a jibe as any Democrat can take at another.

But Byrd is not alone in his belief that Carter was largely to blame for last November's Democratic debacle. Many others in the states and in Congress blame Carter not only for the weakness of his own candidacy, but for his preemption of party resources for his own doomed cause.

An effort has been made to soften the criticism. Les Francis, an able former National Education Association organizer who served in 1980 as executive director of the DNC, put together a lengthy memo to White, attempting to refute the "negative criticisms" of the committee's work.

The memo concedes at the outset that the DNC has been hobbled by the "horrendous debt" still carried over from the 1968 campaign. Actually, that debt was cut by two-thirds to about $800,000 during the past four years.

It observes that "for a variety of reasons, neither the Democratic administration nor the Democratic Congress paid sufficient attention to the DNC in recent years."

It notes that the prolonged nomination fight between Carter and Ted Kennedy sapped the party's energy and its fund-raising ability. But then, Francis argues, under the circumstances the DNC really did quite well.

His evidence is curious. The political targeting program under Chris Brown, he says, "unfortunately performed flawlessly." Carter carried exactly as few states as Brown had predicted he would.

He notes that many basic organizational programs, with long lead times for effective payoff, were begun only in May or June of last year. He notes that he heads of major committee staff functions found themselves in the closing weeks of the campaign working for Carter in Santa Clara County, Calif., in Rochester or in South Carolina.

But he does not make a point of the most telling single fact of all about the relationship between the Democratic National Committee and Jimmy Carter.

It is simply that the man who was making this defense of the DNC, Executive Director Francis, was himself pulled out of his party job to fill in the Carter campaign committee when Field Director Tim Kraft was sidelined by the investigation of his alleged drug use.

The freedom that Carter felt to take whatever or whomever he needed from the Democratic Party -- and not put much back in -- is why his name in party circles is "Difficult Circumstances."