What was going on when I was born?

In every new Administration there comes a time, after the initial policies have been set out, when so much skepticism and political resistance develops that the President must aggressively defend the credibility of his program and his own leadership. With economic forecasts turning gloomy, Europeans jittery about American statements on nuclear warfare, the Israelis acutely nervous about the direction of Washington's Middle East diplomacy and Congress still balking at the economic program, President Reagan confronted that task today. In the public opinion polls, Mr. Reagan remains popular with the electorate. His surprising victory in the Senate 13 days ago on the $8.5 billion package for Saudi Arabia gave him a lift. But neither his popularity nor the Senate victory has restored his earlier legislative momentum or dispelled qualms and questions about his policies.

Apparent discrepancies have arisen about the background of a Republican National Committee official, John A. Kelly, who organized the ''National Ballot Security Task Force'' in the election for Governor of New Jersey. The discrepancies involve challenges to assertions in a biography provided by the Republican National Committee that Mr. Kelly graduated from the University of Notre Dame and from Fordham University's law school. And a spokesman for a national police organization, the Fraternal Order of Police, disputed the biography's assertion that Mr. Kelly had been an officer in the organization. The spokesman, Thomas Tague, said Mr. Kelly was ousted from the group in 1979 after admitting that he had misrepresented himself as a staff investigator for a Congressional committee.

LACK of time, lack of space, lack of expertise -all those are legitimate and often-heard excuses for not giving a dinner party. But in the coming festive season, not having a party is not always an option. So when pressed, the host or hostess will call in a caterer or stop in at the gourmet carryout in order to feed guests with a minimum amount of effort. For some people anything is preferable to the work involved in cooking the meal at home. That's why I thought I had reinvented the wheel recently. I had organized two bring-your-own-dish parties and each was an unqualified success. A few days later, however, I lunched with two friends who told me I had come late to the idea of a bring-your-own party. They have been sharing weekend dinner chores with their friends all summer at various retreats. But they have never done it in the city and neither was certain why. Another friend had an explanation. In the city, she said, it is as if there is an obligation to give the perfect little four-course dinner party. ''People here don't like to admit vulnerability and fatigue,'' she added.

New York City's welfare agency, warned that it may be penalized tens of millions of dollars in Federal funds because of inefficiency, has indicated that it would find it easier and less expensive to suffer the penalty than to correct the mistakes. The warning came from State Comptroller Edward V. Regan and the response from the Commissioner of the city's Human Resources Administration, James A. Krauskopf. Both are contained in a report released by Mr. Regan. Mr. Regan said the penalties, which could total $70 million over three years, would be imposed if the state and the city did not meet Federal requirements for reducing the payment error rate to 4 percent by September of 1983.

Leaders of the American oil industry predicted today that oil prices would stagnate for a year or more. The executives, who assembled here yesterday for the annual meeting of the American Petroleum Institute, said that this meant continuation of a trend that has seen the average price of a gallon of gasoline decline by nearly 5 cents since March, to $1.34. The predictions of price weakness come in sharp contrast to a forecast at last year's A.P.I. meeting by Dan Lundberg, a retail oil analyst, that gasoline prices might reach $2 a gallon in 1981. Nonetheless, oilmen suggested that the good news on the price front carried several worrisome implications: Pressure on refining and marketing profit margins might intensify, development of alternative forms of energy would likely be postponed and the prices of energy company stocks could not be expected to rise.

President Reagan, though adamant about spending cuts, will defer until next year proposing the basic reductions in Federal benefit programs that he had called for six weeks ago. At a news conference, Mr. Reagan made his gloomiest assessment yet of the immediate economic outlook, but predicted that the economy would rebound next spring or early next summer. (Page A1.) Inflation at producer levels continued to ease in October. The Producer Price Index for finished goods rose six-tenths of 1 percent, the Labor Department reported, the biggest advance since April, but economists said that it mainly reflected a jump in the auto prices. But two other important indexes showed no change or declined. (A1.)

The commander of Libya's remaining troops in Chad said today that civil war would return to this country once his soldiers completed their withdrawal and were replaced by an African peacekeeping force. The evacuation of the Libyan troops was requested by the Chad Government, which gained power after Libya intervened militarily last December to support it in a civil war. The Libyan commander, Col. Radwan Salah, said in an interview that the pullout from Ndjamena, the capital city on the brown, muddy banks of the Shari River, would be complete within three days. The withdrawal from the nation as a whole would take about two weeks, he said. The Libyan Air Force, using Soviet-made Ilyushin-76 and American-made C-130 and DC-8 transport planes, began the evacuation last week.

WASHINGTON RESTAURANT fever seems to have hit the nation's capital in epidemic proportions. A relative gastronomic backwater only 10 years ago, Washington now boasts dozens of creditable and fashionable French, Asian and North Italian dining places. Restaurant hopping is the second favorite game in town, nosed out only by politics, and nouvelle cuisine oneupmanship is rampant among would-be superstar chefs, most of them from France. Add to that the festive and lavish climate of the Washington social scene and it is apparent why visitors should make reservations well in advance. Prices are generally equal to those in New York and Los Angeles, which is to say sky-high. Tightly waved and lacquered hair appeared to be a little more prevalent among women in Washington than in New York, and metallic knits are much in view, especially, one suspects, on out-of-towners who apparently require that their glitter be packable.

Poland formally applied today for membership in the International Monetary Fund and the World Bank. Its action opened the door to the possibility of loans from these institutions as a means of dealing with its mounting financial and economic problems. The move, which has been encouraged by West Germany, the United States and other Western powers and now apparently has the support of the Soviet Union, had been expected in the wake of discussions that have been under way in Europe for several weeks. Before the latest discussions, the Soviet Union was understood to have vetoed Poland's earlier wish for membership. There was no immediate explanation about why the Russians changed position, but some Western analysts said it could represent recognition that a Polish economic collapse would be costly to them, as well as for Western financial institutions.

The $4.3 billion merger of the Connecticut General Corporation and the INA Corporation is quite different from the huge mergers that have startled the insurance industry this year, but it was shaped by the same need. The union is a shrewd effort to squeeze out rising costs and stake out an advance position in the rapidly evolving insurance business. The mergers earlier this year were more focused on selling new financial and insurance products to individuals at retail. They included the purchase of the Bache Group, a securities company, by the Prudential Insurance Company of America; the purchase by American Express, owner of the Fireman's Fund Insurance Company, of Shearson Loeb Rhoades Inc., a large brokerage firm, and last month's move by Sears, Roebuck & Company, parent of the Allstate Insurance Company, to buy Dean Witter Reynolds Inc., another securities house, and Coldwell, Banker & Company, a national residential real estate concern.

In recent months Philip Morris Inc. helped bring an Edward Hopper exhibition to the Whitney Museum of American Art and a show on German Expressionism to the Guggenheim Museum. Next year it will help bring works by Kandinsky to the Guggenheim and manuscripts of Lewis Carroll to the Morgan Library. Following recent cutbacks in Federal spending on the arts, education and social welfare, President Reagan has called on business to increase its support of such things. In many respects, Philip Morris, the maker of Marlboro cigarettes, Miller beer and 7-Up, has long been a model of corporate philanthropy. ''In support of the arts, Philip Morris is one of the most progressive companies,'' said Michael d'Amelio, vice president of the Business Committee for the Arts, an organization that promotes company giving.

Three indexes that measure prices at various levels of production indicated a continued easing of inflation during October. The Producer Price Index, which applies to finished goods and is a rough measure of the level of inflation that consumers will face in coming months, inched up by six-tenths of 1 percent in October from September, the Labor Department reported today. Although this was the biggest advance for this index since April, economists said that it reflected mainly a big jump in the prices of 1982-model cars and an end of auto makers' rebate programs. The rebates had helped to keep the rise in the finished goods index in September to just two-tenths of 1 percent.