Ronald Reagan said today that the United States should scrap a foreign policy based on "weakness and illusion" and replace it with one founded on improved military strength.

In remarks prepared for a Lincoln Day dinner speech here, Reagan called for beefing up the U.S. nuclear deterrent and for providing greater protection to U.S. nuclear forces to prevent a successful Soviet first strike. He also urged a naval buildup and said the Central Intelligence Agency should be allowed to pursue covert activities without congressional restraints.

"Jimmy Carter risks our national secrity -- our credibility -- and damages American purposes by sending timid and even contradictory signals to the Soviet Union," Reagan said. "The crisis of confidence which pervades this administration has become a permanent feature of our daily lives."

Reagan's speech marked a departure from past foreign policy pronouncements. For the first time since his campaign began, he spelled out his criticisms -- and his alternatives -- in a message described by his aides as comprehensive.

As recently as a week ago, some of these aides were saying that Reagan would not issue such a statement until after the Feb. 26 New Hampshire primary. But within the Reagan camp there has been concern, expressed by campaign manager John P. Sears and others, that his views were emerging in the press in a fragmentary way. The five-day foreign policy statement issued to some reporters today and used by Reagan in his speech tonight was an attempt to remedy this.

Press secretary Jim Lake acknowledged that the statement was less an effort to say something new than to demonstrate that Reagan has "a coherent, comprehensive view of foreign policy and of presidential leadership." c

Reagan called for:

Maintenance of the U.S. nuclear strategic deterrent. "We must make our nuclear forces less vulnerable so that our adversaries will never be tempted to destroy our missiles and our bombs with a massive surprise attack." Throughout his campaign, Reagan has criticized Carter for slowness in deploying the MX missile defense.

Increasing naval strengths to what ever levels are needed to stay ahead of the Soviet Union.

Restoring capacity to protect U.S. interests in the Persian Gulf and Middle East. Reagan did not give specifics, but he has called for establishment of U.S. military bases in these regions.

An increased budget for military research and development.

"We must once again restore the U.S. intelligence community. Senseless restrictions requiring the CIA to report any and all covert actions to eight congressional committees must be eliminated."

Shoring up alliances with the North Atlantic Treaty Organization nations and with Japan, Canada and Mexico.

"It is time to expand dramatically the Voice of America, Radio Free Europe and Radio Liberty. We have a message of peace and hope and nothing to be ashamed of in the examples we set for the world. Millions upon millions of people look to us as a beacon of freedom in a world that is fast losing freedom. We can convey our deep convictions to the world to combat the hostile and ceaseless communist propaganda that distorts everything we stand for."

In recent days, as foreign policy has increasingly dominated the presidential campaign, Reagan has been sharply critical of Carter. He said Thursday night in Burlington, Vt., that Carter pursues "a foreign policy bordering on appeasement."