The State Department's human-rights office has reached such policy-making eminence that a protest from its boss, Pat Derian, raised the possibility of postponing Vice President Walter Mondale's visit to Manila last week.

Actually, Assistant Secretary of State Derian fought hard not just to postpone Mondale's trip, because it came so close to the much-criticized presidential election there, but to cancel it altogether.

"We wanted to postpone it to July," a top aide in Derian's office told us. "pat kept asking, 'Why in Gold's name does he have to go to the Philippines anyway?'"

In the end, Mondale went as scheduled, but first received a one-hour briefing from Derian on how to handle the delicate human-rights question raised by allegations of widespread electoral fraud by President Ferdinand Marcos.

The expanding policymaking eminence of Derian's human-rights office is raising some prominent eyebrows on grounds that human-rights activists are jeopardizing other U.S. foreign-policy objectives, particularly among conservative and right-wing governments with intimate ties to the United States.

Linked to this concern about everwider ramifications of President Carter's justly praised human-rights initiative is the switch from loud to quiet administration handling of the absence of human rights in the Soviet Union and other communist states.

A case in point was Secretary of State Cyrus Vance's recent mission to Moscow on strategic arms limitation talks. Vance spokesman Hodding Carter was permitted to inform the press that Vance privately complained about Russia's African adventures in his talks with Soviet leaders. But he was not authorized to tell the press that Vance also privately brought up human rights with Foreign Minister Andrei Gromyko.

President Carter's human-rights operatives are embarrased by this dramatic changed to an iceberg policy on Soviet lack of human rights after the gaudy publicity Carter deliberately invoked early in his administration by inviting Soviet dissidents into the White House. They are claiming now that they can achieve more by concealed pressure, a claim that so far defies objective testing.

But in the non-communist world, the unconcealed emphasis on human rights is making troubling noises across Latin America and South Asia. Using the clout of Presidential Directive No. 30, secretly issued to government agencies by the National Security Council on Feb. 17, State's human-rights office has systematically rejected almost every single request from U.S. allies for such routine civil-law-enforcement equipment as tear gas, .38-cal. pistols for police forces, and handcuffs.

What makes that secret presidential directive so virulent, in the view of career diplomats privately fighting the web of human-rights restrictions, is this: Derian's office is using it to reject requests, no matter how routine.

The presidential directive officially inserts human rights into every policy decision. It orders U.S. representiatives on all international lending institutions, such as the Asian Development Bank, to vote against most loans for countries with a single human-rights blemish. The dire implications of the directive are being quietly tested throughout the government.

For example, an appeal is in the works to reverse a human-rights veto of routine police equipment to Singapore (officially described by the State Department as "free from corruption"). In similar rejections for Taiwan and South Korea, weeks have been consumed in the appeals' process. One appeal went to the desk of Vance himself, who bucked it back to Deputy Secretary of State Warren Christopher, top human-rights coordinator. Adjudication of Derian's decrees are consuming an inordinate amount of bureaucratic time.

What is happening to U.S. allies in Asia afflicts longtime U.S. allies in Latin America at least as sharply. Menawhile, the communist world, which is generally beyond the commercial or political reach of the United States, is untouched by the unpublished presidential directive.

This trend in Carter's human-rights crusade is seldom publicly criticized within the administration. Terence Todman, who is about to leave his post as assistant secretary of state for Latin American affairs, did raise pointed questions about it in a speech three days before the Feb. 17 presidential directive. But for warning against human-rights moves "without calculating the likely reaction and responses" abroad, he was rebuked by high officials at State.

That shows the clout of Pat Derian, the sincere but total advocate of making the United States the conscience of the non-communist world.