We've come to a curious crossroads in foreign policy. The Reagan Doctrine proclaims American support for anticommunist revolutions around the world. For practical purposes this means (in descending order of remoteness from the United States) in Afghanistan, Cambodia, Angola and Nicaragua. Congressional liberals, by and large, seem to have responded. They will support half.

The scorecard reads like this:

-- Afghanistan. No argument. For liberals, as for conservatives, as for the mujaheddin themselves, it is holy war.

-- Cambodia. The author of overt military aid to the noncommunist guerrillas is the leading liberal foreign policy thinker in Congress, Rep. Stephen Solarz.

-- Angola. Congress is soon to vote on the question of aid to Jonas Savimbi's UNITA rebels. The strongest opposition comes from House liberals, led by Solarz.

-- Nicaragua. Liberals overwhelmingly oppose aid to the contras.

What is curious about this lineup is that liberals, by reputation, are guided more by considerations of human rights and democratic forms than conservatives. Yet, compared with the insurgencies they oppose, the insurgencies they favor are likely to produce regimes far less disposed toward either human rights or democratic forms.

In Cambodia, we do support good guys. But they are dominated by much more powerful allies made up of very bad guys, the Khmer Rouge. If the rebels were to triumph tomorrow, it is Pol Pot, or his disciples, who likely would rule. When Pol Pot last ruled Cambodia, he proved himself the greatest murderer since Hitler, Stalin and Mao, and they had advantages of scale.

In Afghanistan, there is much to be said for the courage and patriotism of the mujaheddin. There is less to be said for their interest in the theory and practice of democracy. Were our side to win, it would probably produce a regime politically, as geographically, somewhere between the dictatorship of Pakistan and the Islamic fanaticism of Iran.

Next to their Asian brothers-in-revolution, an Angola under Savimbi or a Nicaragua under, say, Arturo Cruz looks positively Jeffersonian. Thus purely from the point of view of political morality -- of what life for the people will be like if our side wins -- support for the Asian half of the Reagan Doctrine and opposition to the rest is incoherent.

Accordingly, in support of this peculiar policy, and in preparation for the upcoming vote on Angolan aid, a search for coherence has been undertaken. This is what it has turned up.

1.International law. Some argue that because Cambodia and Afghanistan have been invaded by foreign troops, only there is U.S. support for the insurgents justified. It is not clear, however, why the address of one's op pressor should be decisive in deciding whether resistance is legitimate or whether it deserves American support. Poland was not invaded by Gen. Wojciech Jaruzelski. Is the resistance to his rule any less deserving for that fact?

Moreover, this is a strange argument to make in defense of an Angolan regime propped up by 30,000 Cuban troops -- which makes Angola one of the last sub-Saharan countries that can be said to be white-ruled. The armed foreigners in Luanda will undoubtedly claim that they were invited by the local pseudo-regime. But so can the Soviets in Kabul and the Vietnamese in Phnom Penh. Nowadays, etiquette demands that occupation be by invitation only.

2.Apartheid. A more serious and special charge against Savimbi is that he takes aid from South Africa. No one says that Savimbi has any sympathy for apartheid, because that would be absurd. Savimbi is a life-long black nationalist who has been fighting one or another form of colonialism for 20 years, including many years spent fighting Portuguese colonialism when it was supported by South Africa.

The help he gets from South Africa is a matter of pure convenience. Or, more accurately, necessity: for 10 years, the other potential source of help, the United States, was cut off by the Clark amendment. Savimbi had to choose between clean hands and survival. To the dismay of some, he chose survival.

But Savimbi is no more an agent of South Africa than Washington was of Louis XVI. Savimbi takes Pretoria's aid because he has no choice. The United States can give him the choice. American aid could replace Pretoria's aid. It could even be conditioned on Savimbi's dissociation from South Africa. That would free him -- and us -- of the South African taint.

Which suggests that there may be yet another principle underlying the selectivity of the liberal response to the Reagan Doctrine:

3.Distance. What distinguishes the insurgencies of Cambodia and Afghanistan is that they are the farthest away. Far enough away that their true nature does not too readily come into focus. It is much easier to support out-of-sight intervention, wars whose violence is far beyond the ken of American cameras and American consciousness.

Solarz opposes the "global interventionism," as he calls it, of "the high priests and acolytes of the far right," as he calls those who differ with him on the Reagan Doctrine. His alternative, it seems, is hemi-global interventionism: the United States will support any insurgent, provided he is more than eight time zones away. Call it the Solarz Doctrine.