Sen. Albert Gore Jr. (D-Tenn.) yesterday intensified his attacks on his competitors for the Democratic presidential nomination, charging that all five are opposed to temporary nonmilitary aid to the Nicaraguan contras because "they are scared to death of being outflanked on the left."

Gore charged that the leftward tilt of the early Democratic caucus process in Iowa has prompted all of his opponents for the nomination to oppose the nominal funding despite the fact that it was endorsed by the House Democratic leadership and that Costa Rican President Oscar Arias said the aid would not conflict with a peace plan for Nicaragua.

"They are scared to death of a 10-second commercial," Gore said at a luncheon meeting with reporters and editors of The Washington Post.

William Carrick, campaign manager for Rep. Richard A. Gephardt (D-Mo.), countered that Gore's charges "are phony -- you know what his record is," contending that Gore's voting record on defense issues is almost identical to Gephardt's.

"Gore only discovered the deficiencies in the process when the voters discovered the deficiences in his candidacy," Carrick said. "It's easy for him to say -- his candidacy is DOA out in Iowa." The Gephardt campaign released a list of 16 major defense and foreign policy votes that showed no difference between the stands of Gephardt and Gore.

Gore is, however, the only Democratic candidate to support the $3.5 million in nonlethal aid to the contras approved last month by the House. In addition, he said, few if any of the other Democratic candidates supported putting U.S. flags on 11 Kuwaiti ships in the Persian Gulf and, with one exception, all of his opponents support a ban on missile testing, a step he opposes.

"There is a neo-isolationist impulse that has come out of the Vietnam experience that has not been put in perspective in the {Democratic} party," Gore said. "The nominating process has served to push the candidates to the left and make each of them scared they will be outflanked on the left by someone who plays to this neo-isolationist impulse. Therefore the mainstream Democratic voter listening to the dialogue feels disillusioned and confused about where the traditional Democratic consensus has gone. I'm letting the others succumb to those pressures and holding my ground in the center."

When asked to describe his reasons for joining the presidential race, however, Gore cited as his major goal the achievement of an arms control agreement with the Soviet Union, using language much like that of other Democratic candidates:

"I sincerely believe that I can do a far better job of handling and maximizing this historical opportunity {to negotiate with Soviet leaders} than anybody else in the race on either side. I sincerely believe that I have a clear understanding of exactly what needs to be done and how to go about it."

Asked to provide specifics, Gore indicated support for a plan to restrict both the Soviet Union and the United States to a relatively small number of mobile, single-warhead missiles. The logic is that such a restriction would ensure that neither side would consider a first strike because it would be impossible to locate and destroy all of the opposition's missiles.

On domestic economic issues, Gore declined to rule out the possibility of raising taxes -- "it {the option} has to be available . . . Taxes may have to be part of the solution" -- but he pointedly noted: "I am not proposing a tax increase."

If the country is headed into a recession, he said, a tax increase would only worsen the situation. Referring to the sharp decline in stock market prices earlier this week, Gore said: "What crashed on Monday was not only the market, but Reaganomics as well."