IT SHOULD COME as no surprise that top officials of the Reagan administration are sending out conflicting signals about how the United States should deal with terrorism. To someone who has often worked among those called terrorists by one side or another, it seems American interest in the subject has never moved beyond slogans and threats. The incoherent debate in Washington over a how-to manual for anti-Sandinista rebels in Nicaragua helps explain why.

Congressional committee members are investigating how the Central Intelligence Agency could have supplied guidelines that advocated assassination by another name and seemed aimed at overthrowing the Sandinista government. This, they contend, is not what they were told during briefings by the agency. U.S. law clearly forbids assassination, and wasn't our policy only to interdict arms shipments to Salvadoran rebels and pressure Sandinista leaders?

These same committee members have approved an estimated $80 million to finance rebel activities against the Sandinistas since 1981. Presumably with their knowledge, some of the money went for AK47 and FAL assault rifles, explosives and mortars. Some went to feed and clothe the 10,000 Nicaraguans, mostly young peasants, who have joined rebel ranks.

Did anyone on those committees seriously believe the automatic rifles were to be used only in Geneva-Convention engagements with the regular Popular Sandinista Army? Did anyone believe the explosives were not going to blow up civilian targets, including people, as has been the case in all guerrilla wars? Did anyone really accept the idea these Nicaraguan rebels were going into hostile mountains to live like hunted animals for months at a stretch only to support President Reagan's policy of harassing the Sandinistas?

I can only believe not. Leaders of the main rebel group, the Nicaraguan Democratic Force, freely tell reporters their objective is to overthrow the Sandinista government. We report back on what they say, and it appears in the newspaper. Sandinista officials complain constantly about civilians killed by guerrilla attackers. We report back on what they say also, and it appears in the newspaper. Sometimes, when we are lucky or particularly resourceful, there is on-scene verification. Again, it appears in the newspaper. No, I cannot believe congressional committee members had no idea the funds they approved were paying for, among other things, assassinations carried out by Nicaraguans resolved to overthrow their country's government with U.S. help.

Instead, the concern seems to focus on seeing all this written down in a manual compiled by U.S. officials. We who monitor these problems from within countries where they are occurring always wonder about Washington's fascination with words over deeds. But it is a fact, and once again we are seeing it in action. The deeds of anti-Sandinista rebels are fairly well known, and have been for some two years. Now suddenly a manual putting these deeds into print -- "neutralize" -- is an issue.

Maybe this is so because the U.S. government has always taken the high ground in discussions of terrorism. When Syrian intelligence helps Islamic extremists "neutralize" U.S. military or diplomatic installations, the administration and Congress harmonize loudly to condemn state-supported terrorism. Now they are face to face with official U.S. guidelines that read like the same thing.

The anti-Sandinista guerrillas have been engaging in such acts with CIA guidance for some time, bombing Managua's main airport, torching food warehouses and taking out Sandinista officials along mountain roads. But that this is written down somewhere apparently gives it new reality.

Perhaps by accident, Secretary of State George Shultz chooses the same moment to suggest the United States should respond to terrorist attacks by striking back even if the target is uncertain and innocent people may get killed in the process.

In other words, bomb Islamic extremists in the Bekaa Valley of eastern Lebanon even if U.S. intelligence is unsure those extremists are planning another strike against U.S. targets and even if some Lebanese marijuana farmers get blown up as a byproduct. This policy has been used by Israel, although it has created a lot of enemies.

If such a policy were adopted by Nicaragua, however, Sandinista planes could be expected to attack such points in Honduras as Las Vegas, where the anti-Sandinista rebels have a large base camp, or perhaps Tegucigalpa, the capital city where they operate from several large homes.

This, of course, is not what Shultz has in mind. For the Reagan administration, the anti-Sandinista rebels are not terrorists but freedom fighters. The same is true of Afghan rebels fighting with CIA help against a Soviet-sponsored government in Kabul. But in a policy such as Shultz has outlined, it is the aggrieved government planning to strike back that defines who the terrorists are.

So if for the United States Islamic extremists are terrorists, then perhaps for the Sandinistas the U.S.- supported rebels in Honduras also are terrorists, or perhaps for the Soviets in Kabul so are the Afghanis operating out of Pakistan.

One man's state-supported terrorist is another's freedom fighter. If for Clausewitz war was the continuation of politics by other means, then for the nations of 1984, state-supported terrorism is the continuation of cold war by other means.

A straightforward solution is to respond in kind, as Shultz seems to be suggesting, and damn the consequences. Israeli governments traditionally pursue this course and thereby earn the respect of most nations, particularly ours (though not of any Arab states). But the uproar over the anti-Sandinista manual suggests the U.S. Congress might not tolerate for the United States what it applauds for Israel.

Another solution is to stake out the high ground and stay there in deed as well as word. The outrage over "neutralize" would then extend to outrage over sponsoring freedom fighters, or terrorists to the other side. You cannot have it both ways.