Ronald Reagan charged today that the Carter administration had handed military superiority to the Soviet Union and placed U.S. security in jeopardy. He promised that if he is elected president he will try to make the United States militarily first again.

Denouncing Secretary of Defense Harold Brown for describing the impulse toward military superiority as "unrealistic, simplistic, dangerous," Reagan told a cheering audience of more than 4,000 American Legionnaires:

"Since when has it been wrong for America to be first in military strength? How is military superiority dangerous?"

Reagan accused President Carter of "cynically and belatedly" trying to take credit for restoring cuts he himself had made in the defense budget. And the Republican presidential nominee hinted that the Carter administration might take provocative action during the election campaign in an effort to prove that American military power is adequate.

"The military policies of the Carter administration are in disarray," Reagan said. "The weakness of those policies can ultimately become provocative. We must hope that this administration will not be tempted to take reckless actions designed to assure Americans that our power is undiminished. The facts are we lack the capability to project our power to many areas of the world."

James Brady, a Reagan aide, said that this passage was not based on an assumption that the Carter administration was planning a military adventure in Iran or elsewhere. But Brady added, "We fear that domestic politics will be brought into foreign policy in this election campaign."

The speech was Reagan's third on national security issues in as many days, and it broke little, if any, new ground. Every accusation Reagan made today he has made many times since he launched his presidential campaign last November.

Reagan did not spell out what particular weapons systems he favors to restore U.S. strategic superiority. Nor did he put any dollar figure on the defense budget increases he favors.

But before the same veterans convention that Carter will address Thursday, Reagan outlined the national security objectives he would pursue as president.

"Our nuclear deterrent forces must be made survivable as rapidly as possible to close the window of vulnerability before it opens any wider." Reagan said, "We must immediately reverse the deterioriation of our naval strength and provide all of the armed services with the equipment and spare parts they need.

"We must restore true essential equivalence for our own security and for the political perceptions of our adversaries, our allies, and Third World countries," he said.

Scattered throughout his speech were some harsh references to Carter, whom Reagan denounced for "sheer, blatant hypocrisy" in attempting to represent that the U.S. defense posture has improved under his administration.

". . . By such untruthful devices as manipulating inflation factors, shifting the base from authority to cutlays, changing base years and even ordering planned defense spending this year reduced so it would look as if he had met his promised percentage increases for next year, the Carter administration tries to manufacture increases that in fact are largely phoney," Reagan said.

Later, before touring the USS Constitution in Boston harbor, Reagan issued a statement saying that "Carter's shipbuilding program is clearly inadequate to meet the Soviet threat, which ultimately is a threat to peace"

The statment issued by Reagan at the Constitution -- a 1797 ship that distinguished itself as "Old Ironsides" in the War of 1812 -- joked that "if this Carter trend continues, we'll have to return [the Constitution] as a first-class ship of the line."

One of Reagan's loudest applause lines at the Legion convention came when he promised to "implement a program of compensation and benefits for valued military personnel comparable to what is available in the private sector."

Reagan also urged immediate restoration of the GI Bill for educational benefits, which he called "one of the most effective, equitable and socially important programs ever devised."

Three pending Senate bills to provide educational benefits for military recruits when they leave service would cost between $500 million and $1.7 billion a year. Reagan aides have no cost estimate on what it would take to make military pay and benefits comparable to private compensation.

Last month in Detroit, Reagan used the figure $6 billion as the estimate of what it would take to improve pay and incentives so that the United States could maintain a volunteer Army and improve the quantity and quality of its Ready Reserve.

The actual cost of Reagan's proposals is likely to be an issue in the fall campaign because the Republican presidential nominee also maintains that taxes should be cut and the federal budget balanced. Reagan favors the all-volunteer Army and opposes the recently started Carter draft registration plan.