Ronald Reagan sugarcoated the pill in current Soviet-American relations in his State of the Union message, but it remains a pill -- a bitter one, perhaps becoming more bitter -- and there is little sign that the president has figured out how it will go down.

The pill is the package of regional disputes that lie between Moscow and Washington. In Nicaragua, Afghanistan, Angola and Cambodia, insurgents supported one way or another by the United States are fighting against governments backed by the Soviet Union. Few people can see any of these conflicts as getting anything but sharper and rawer in the foreseeable future.

The sugarcoating consists of President Reagan's delicate attempt to "de- link" these disputes, in two ways, from pursuit of arms control.

De-linking in diplomatic tactics: Reagan went to the summit last November pledging to keep the regional disputes front and center -- a hint that he might make Soviet Third World restraint or concession a condition of whatever arms control steps became possible. But he has since moved arms control and these disputes into seemingly airtight pockets. "Seemingly": everyone understands that if a dispute got really hot, all arms control bets would be off.

Implicitly Reagan has neared the position Gorbachev occupies explicitly: "The Soviet Union is opposed to making the implementation of disarmament measures dependent on the so- called regional conflicts." This is a formula, of course, not merely for fencing off arms control but for continuing or even for sharpening great-power competition in the Third World.

De-linking in word: A year ago Reagan promised support to the familiar four guerrilla movements, identifying the deeper threat they pose as "Soviet- supported aggression." In the interval he began direct dealings with the Kremlin, and now, though he remains faithful to the four insurgencies, he does so without making an open point of their connection to Soviet power, though that connection is as real as ever.

To take the president at his word, the sugarcoating may wear off soon. In his speech he notched up his commitment to the four insurgencies. Last year his pledge -- earnest but rather noncommittal -- was "not to break faith" with freedom fighters. This year, in an evident response to the common criticism that American aid has been too skimpy to matter, he pledged moral and material assistance "not just to fight and die for freedom but to fight and win freedom -- to win freedom in Afghanistan, in Angola, in Cambodia and in Nicaragua."

One can argue about what it might mean to "win freedom" in those four places: about the nature of the freedom being sought in turn by the Arturo Cruzes in Nicaragua and the Moslem fundamentalists in Afghanistan, about the difference between the strong Jonas Savimbi in Angola and the weak Son Sonn in Cambodia, about the disparity between the American interest in who rules nearby Nicaragua and who rules distant Cambodia, and so on.

Presumably the answers to these questions -- vital questions that believers in anticommunist insurgency tend to brush past -- will be clearer after President Reagan sends Congress his message on regional conflicts following the February recess.

Meanwhile, Gorbachev surely will notice that the president is not merely promising to hang in there with the four insurgencies. He is setting more assertive goals for American policy -- to "win freedom." In the State of the Union anyway, he uttered not a word about negotiating political settlements. In the insurgency -- in Nicaragua -- where American aid is discussed most openly, he plans a big increase that would put aid into the $100 million range. Congress, too, is bound to notice Reagan's new measure of commitment. Last June and July the swing bloc of House Democrats, previously more or less hesitant, moved more boldly in respect to each of the four insurgencies. But the Democrats did not move the whole way or the particular way that Reagan wanted in respect to any of the four.

Now the president will be back, pushing -- he warns -- hard. The coming battle and maneuver over the "Reagan Doctrine" of aiding anticommunist guerrillas promises to provide one of the leading spectacles of the year -- an election year, some have noticed.

With Reagan in nuclear negotiations, which are hard for a broad public to follow, the burden of public engagement in foreign policy inevitably shifts to these tricky questions of Third World intervention to bestow democracy and freedom. Watch out.