Nothing better illustrates the surrealistic, cracked- mirror character of government secrecy edicts than a pair of actions by President Reagan last week.

The president signed an executive order on Friday requiring all federal employees with security clearances--a number reaching into the hundreds of thousands--to submit to lie-detector tests in any investigation of leaked information, or suffer "adverse consequences" for refusing. On the very same day, he stonewalled a press conference question about leaks from his own senior staff that undermined the position of Environmental Protection Agency head Anne M. Burford in the days before her resignation. "I don't know of anything of that kind," Reagan said.

As an example of high comedy, you could hardly improve on that script.

Every reporter in town knows that Reagan did not have to walk more than 50 feet from the Oval Office to find people in his employ who were leaking like crazy that Burford would have to go. "I know that you were all citing these unnamed White House sources that thought she would resign," he told reporters. "I still would like to find them out and identify them."

But he has not. Instead, he has issued the most sweeping secrecy edict in the history of the civil service. The seemingly misplaced emphasis reveals what no government--at least as long as I have worked in Washington--has ever wanted to acknowledge: what bugs a president is not leaks, but leaks from people who may disagree with him.

Time after time, in administration after administration, colleagues and I have sat in the office of some senior official who, promised anonymity, has divulged the substance of, or even read from, highly classified documents. The purpose, in almost every case, was to advance the president's policy line--in Vietnam, in some international negotiation, in some domestic political fight.

No, it's not the leaks that infuriate them. It's the leaks they don't control: the logs of private meetings with interested parties in regulatory matters, or evaluations of weapons systems that cast doubt on a multi-billion-dollar boondoggle. Those leaks, they say, are dangerous.

So be aware, dear reader, of what is really going to happen if Reagan is allowed to tie a lie-detector threat to the tail of every career official of any standing. It will not stop the leaks. The president or his people will no more play by the rules of the executive order than the Reagan aides obeyed his supposedly serious order to stand by the embattled Burford. What the executive order will do is shut down your access to information that may contradict or cause you to question the policy judgments of the president and his aides.

It will increase substantially the risks for anyone --bureaucrat or journalist--who wants you to hear the other side of the policy argument from the one the president is peddling. And, while it lasts, it will increase the odds that the policy adopted will be worse than it would have been had the rules of debate--or leaking--been applied evenhandedly to friends and foes of the president's policy.