Ronald Reagan preached the gospel of the "new economics" in Washington yesterday, predicting that disillusionment with the Carter Administration would attract blue-collar Democratic voters to his candidacy.

"Political experts used to tell us there were social issues and economic issues," Reagan said in a speech to the American Society of Newspaper Editors. "Today, the economic issues are the primary social issue. The economic disaster confronting the United States hurts family values, destroys family savings and eats away the very heart of family hopes and dreams."

Neither Reagan's speech nor his answers to a variety of foreign policy questions asked by a panel of journalists drew applause from the editors, who will have heard from all the major presidential candidates before their convention adjourns this week.

Reagan, usually relalxed and informal in question-and answer sessions, appear tenser than usual in his first Washington speech since the day he launched his candidacy last November. Before the panel discussion he quipped, "Do I get a cigarette and a blindfold?"

The only ground Reagan broke on any issue during that panel discussion was to amend his position on the Carter administration's proposed boycott of the Summer Olympic Games.

Reagan originally supported the boycott as a proper protest against the Soviet invasions of Afghanistan. Last week in Kansas he said he "would leave that decision to the athletes themselves."

Yesterday, he said he still hoped that the athletes and the U.S. Olympic Committee would decide to boycott the Games. But he said the athletes should not be compelled by presidential order to participate in the boycott if they vote to go to the Games.

The issue appeared likely to become a matter of controversy within the Republican Party. In Harrisburg, Pa., last night, Reagan's leading challenger, George Bush, took the opposite stand.

Bush said "President Carter made the right decision" in asking for a boycott because it is "the only way the Russian people will learn the truth about Afghanistan." Bush said he knew "it is tough on the athletes . . . But at some point, when a president makes a decision, he's entitled to the support of the nation . . . to make it stick."

On the Afghan situation, Reagan said he would have "no philosophical objection" as president to supplying the Afghans with weapons to defend themselves against the Soviets.

The panelists failed to draw Reagan into a discusion of what he would do to free the American hostages in Iran if the administration's sanctions against the Iranian government do not succeed. Reagan criticized the sanctions as ineffective but said, as he often has in the past, the only the president knows the full range of options on which to base a decision for further action.

The former California governor's prepared speech was devoted almost entirely to economic issues. Stressing the basic monetary message of his campaign, Reagan called for a balanced budget, 30 percent federal income-tax reductions over a three-year period, indexing of income taxes and elimination of the federal inheritance tax.

Reagan's view of the ecnonomic issue as a social-issue emphasized the damage he said was being done to families both by deficits and inflation, and by unemployment as a remedy for this inflation.

Reagan said that high taxes and slow-growth policies were discouraging productivity and reducing incentives. And he mocked administration suggesting that the American people were losing confidence in their institutions.

"Americans aren't losing their confidence, they're losing their shirts," he said.

Reagan did not give specific details of how his programs would simulateously spur economic growth and curb inflation. Nor was he asked about it by any member of the panel.

Reagan was asked from the audience whether he thought Carter had told "lies" to the American people. Reagan said the word was "too blunt" but accused the president of "untruths" and broken promises.

As an example of the latter, Reagan cited a statement Carter made in the second debate with President Ford in 1976 when Carter said he "would never let the friendship with the People's Republic of China stand in the way of the perservation of the independence and freedom of the people of Taiwan." Reagan has said frequently on the campaign trail that Carter "betrayed" Taiwan by withdrawing recognition and recognizing the People's Republic of China instead.