Turmoil within President-elect Reagan's national security transition, which now begins to threaten his policy goals, erupted Nov. 17 in the sudden resignation of an exasperated Laurence Silberman as leader of the CIA transition team.

The proximate cause was the exclusion of Silberman, considered a possibility to be Reagan's director of Central Intelligence, from CIA briefings for the president-elect. Silberman denied to us a policy reason for quitting. "I don't have the time to deal with the complications," said Silberman, a San Francisco banker. Whatever the true causes, a shock wave of paranoia was felt through the national security community.

Silberman, who stood up to then-secretary of state Henry Kissinger as ambassador to Yugoslavia in 1975-77, is a tough-minded realist whose permanent loss would be a serious blow for anti-detentist Republicans. His departure deepens fears among like-minded members of Reagan's transition organization that they are losing during the interregnum the vital defense issues that Ronald Reagan promoted during the campaign.

If Silberman is gone, there are fears that William Van Cleave's days are numbered. Van Cleave, a former SALT negotiator and a steadfast critic of Kissinger-style diplomacy, is under intense attack as leader of Reagan's national defense transition team. The reason given by his transition superiors is personal style ("Bill just comes over too hard"). But the overriding cause is Van Cleave's insistence on radically higher spending to restore the depleted U.S. defense posture.

Van Cleave's team members see an anti-defense-spending squeeze inspired by Nixon-Ford administration retreads and directed through William Timmons, a former Nixon-Ford White House aide who is Reagan's deputy director of transition. Behind Timmons, they see the menacing specter of Henry Kissinger, resurrected in influence though not in person.

Much more pressure has been directed against Van Cleave than Silberman. But tough-talking Larry Silberman does not stand for much nonsense -- such as dismissal from the Senate Intelligence Committee's Republican staff of three aides because they joined Silberman's transition team. Silberman was not pleased when this abrupt action by the committee's senior Republican member, Sen. Barry Goldwater, was backed by his superior in the sprawling Reagan transition bureaucracy: national security group director David Abshire.

Abshire, a former asssistant secretary of state, is chairman of Georgetown University's Center of Strategic and International Studies, where Kissinger has an office. Silberman was not enchanted by the requirement of constant transition reports to Abshire. Nor did he get much help from above in confronting lame duck CIA Director Stansfield Turner's non-cooperation. The last straw came when Silberman was barred from the CIA briefing.

Silberman's resignation was a shock to Reagan's senior echelon, which would welcome a similar departure by Van Cleave. While Van Cleave's brusque personality is stressed as the source of his troubles, he never has been forgiven for telling the hard truth during the campaign: defense spending increases exceeding 7 percent a year will be needed to restore the nation's defenses.

In current discussions at the Pentagon, Van Cleave's team members are laying out the tough requirements: strengthening the Minuteman missile, accelerating the MX mobile missile program, reviving the B1 bomber. That angers Timmons, who contends the transition team has no such mission, and worries Reagan's economizing budget-makers out in California (led by Caspar Weinberger).

Van Cleave's men have found common cause with Pentagon offficials who silently endured the last four tragic years of defense decay. But they have outraged lame duck Defense Secretary Harold Brown, who presided over those years. Brown has complained, through White House channels, about the size and persistence of Van Cleave's team and the presence on it of a congressman -- Rep. Robin Beard of Tennessee.

Beard was removed from the team, and the impression was given that Brown's complaints received a sympathetic ear from Reagan transition leaders. Van Cleave and Co., accustomed to defeat in years of struggle for a stronger defense, have felt a Kissingerian cloud rolling over them.

That may explain an ugly exchange between Van Cleave and Abshire's deputy, defense consultant John Lehman. Although Lehman's hardline defense credentials and courage in fighting SALT concessions equal Van Cleave's, he is a former Kissinger aide and present Kissinger firend. Consequently, Van Cleave rejected four aditions to his team proposed by Lehman, stigmatizing them as the invasion of the "Gucci-loafer set."

Instead of battling Lehman, Van Cleave had better join him. Their common enemy is Weinberger and other economizers who resist drastic but necessary jumps in defense spending. The president-elect's critically important arms program can afford neither turmoil in his own ranks nor the loss of such doughty battlers as Larry Silberman today and Bill Van Cleave maybe tomorrow.